Are there any "completely" remote spectroscopy setups?
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Yes it is possible to set up a remotely operated spectrograph. A good example is the French amateur 2SPOT team who have both a low resolution slit spectrograph and a high resolution echelle spectrograph operating remotely at a telescope farm in Chile. I believe it also operates autonomously (ie acquiring the target automatically) which is quite a bit harder with spectroscopy compared with imaging
My more modest setup is also operated mostly remotely (except for swapping spectrographs and a few manual adjustments) but only over a few tens of metres over wifi from the house
AAVSO also have experience over many years of trying to operate spectrographs remotely (not all of it good as I understand) Arne Henden would probably know more about this
As Robin mentions, it is straightforward to run a spectrograph remotely - it is really no different than having desktop access to the computerized telescope in your backyard. The two main problems are computer control of any adjustment needed in the spectrograph and whether you want fully autonomous operation.
There are several commercial spectrographs that offer computer control, including the UVEX and the SX-spectrograph pro. The FlexSpec-1 spectrograph described in the Society for Astronomical Sciences proceedings, was designed from the beginning for remote operation - but, you have to build it yourself. I've gone that route.
Autonomous control is much harder. You can usually script to change between flat/cal/science spectra for a single object, and programs like PHD2 can guide a target on a slit. Moving between objects and automatically acquiring new targets is a harder challenge. I can't recommend any specific software, as I haven't had a chance to use any of them. I suggest you avoid this step for now, when you are just getting started.
AAVSOnet has several SA200 diffraction gratings in various telescopes, and they work great for low-resolution studies. Even with an R=100 or so, you still have 20x more spectral resolution than with wide-band filters like Johnson/Cousins or Sloan. We have one eShel mounted at OC61, but won't start using it until that telescope finishes its upgrades.
That said, the AAVSO does have one interesting spectrograph - the SBIG DSS-7. This is a low resolution, but fixed in adjustment, spectrograph that was optimized for the ST-7 camera. It has never been used, and it would be nice to experiment with, and once working, put it on an AAVSOnet telescope. Robin, have you ever heard of anyone using one of these?
No I dont know anyone still using a DSS. The SBig DSS and SGS were the only commercial offerings around when started around 2003 but I could not afford one so when the LHIRES kit came out I jumped at the chance. (Oddly SBig got out of that market just at the time amateur interest in spectroscopy was taking off). As Hamish said, the problem with the DSS was than it did not have a built in guider, just a flip mirror so once you flipped the mirror out of the way you were flying blind. The only way to use it on stars rather than extended objects was to use a wide slit, effectively running slitless or defocus the star so exact guiding mattered less. The SGS was much better in that respect as it had a built in guider using SBig's double sensor cameras, a system similar to that adopted by all subsequent instruments.
Do you know if the AAVSO still has its old SBIG DSS-7 spectrograph? I hate to think of it going unused. I'm just getting into slit spectroscopy and would enjoy trying out the DSS-7 if AAVSO would ever consider loaning it out for a week or two (I'm an AAVSO member). Do you think that's possible? Thanks for any thoughts on this!
My ultimate goal is to remotely operated a spectrograph in the backyard observatory.
When I looked at the hardware mentioned above it was clear I lacked the spectroscopy knowledge to make decisions about which hardware to purchase.
After a three month hiatus I purchased the Star-Analyser-200 which will be loaded in the 50mm square filter wheel of the CDK17 (FR-6.8 and FL-2934mm) with QHY600MM.
At present, there are too many unknowns for further hardware upgrades. Hopefully in the future things will be clearer.
I have two other instruments that can be dedicated to spectroscopy
- C14 EdgeHD (F-11 and FL-3910mm) w/reducer(FR-7.7 and FL-2737)
- 140mm APO refractor(FR-7.5 and FL-1050mm) w/reducer(FR-5.7 and FL-798)
I know of one company that sells a remotely operated spectroscope: Starlight Express (SX Xpress). I have one of their earlier models that is not fully remote.
Their fully remote model allows you to focus, change the range of the spectrograph, and turn on/off the internal calibration lamp. It uses mirrors, not lenses so it can extend into the UV and IR. It also has a built-in Lodestar for tracking.
Please do not take this as an endorsement of their product. I'm still learning how to use it with mixed results. Advertised R value is 2000.
I'm trying to automate my dome in s/w New Mexico so that it can be operated from my home in Virginia. (Also the location of my wife.) Having my shutter cable snap recently didn't help.
From what we could test at 2SPOT, there are 3 spectrographs that can be remotely controlled without any problem. These are 3 of the spectrographs from the Shelyak manufacturer:
- ALPY 600 in low resolution R=600 very stable because very compact. Once set, the spectrograph does not move. You can remote control the calibration lamps (flat lamp and Ar/Ne lamp)
- UVEX : you can choose your resolution with different gratings to have a resolution between 600 and 6000. You can control remotely the internal focus of the spectrograph, the rotation of the grating (thus the desired wavelength range) as well as the flat lamp and the Ar/Ne lamp for the wavelength calibration
- eShel : a spectrograph with a high resolution of R=11000 which allows to have in one time all the wavelengths between 3900 and 7600 Å. It is a fiber optic spectrograph that can be adapted to any kind of telescope between f/6 and f/9
In terms of buying, the motorised version of the Shelyak Uvex plus their calibration module would include all the motors and interfacing to operate the spectrograph fully remotely. But as Robin says, there's a big difference between remote and automous. Remote meaning the operator is sitting at a remote computer but operating the spectrograph in real time whereas autonomous meaning the operator sets up a run and goes to bed / the movies/ dinner and comes back to see a fully completed observation run.
The main difficulty in getting autonomous operation working is to reliably position the target star on the slit to a precision of less than a pixel, but the position of the slit in the guide camera field of view may move a pixel or two as equipment flexure and/or thermal expansion happens. But not only 2Spot but also some others have achieved this with a combination of scripts and platesolving.
I operate my own equipment set up in the backyard from inside the house via a long permanent ethernet cable, as wifi was a bit unreliable. I have remote operation of the following:
- mount, of course (but manual polar alignment, however I leave the mount set up and protected from weather, and just install the optical tube with all equipment as a single lift at the start of the night)
- remote focus of the telescope
- servo operation of mirror for the calibration lamp, and relay for the calibration arc lamp
- servo operation of a flip mirror to send the telescope output to a large chip camera for platesolving, or direct to the spectrograph.
- guide camera on the spectrograph
- science camera on the spectrograph
- large chip dslr for platesolving. the field of view of the spectrograph camera which views the reflective slit plate is small, the image quality is not the best due to aberrations in the relay optics, and also extra reflections from the uncoated front surface of the slit plate, so platesolving the guide camera image often doesn't work. Hence I capture a platesolving image with the dslr, use the solved position to synchronise the pointing direction, and achieve centering of any coordinates to within less than 10 arcseconds before switching to the guide camera and adjusting the target the final few pixels onto the slit for guiding during the long spectroscopy exposures. I am usually using several exposures of 1200seconds for the target star when at the faint limit of my equipment. Calibration stars are usually circa 60 second exposures at circa magnitude 6.
In a normal night, the only manual operation I have to do at the telescope is to switch on the halogen flat lamp shining at the white wall near the telescope for spectrograph flats.
My L200 spectrograph is set up for low dispersion as I am usually attempting to take spectra of transient objects tend to be faint and also want wide band spectra, mainly because that is what gets listed on the various automatic survey websites (GAIA alerts, ASASSN survey, CBAT etc) more often. As a result, I am almost always leaving my spectrograph grating set for the band from a bit redwards of H alpha, up to around the Hydrogen gamma line, and don't really need remote operation of the grating setting. However, I have recently been thinking about installing an extra stepper motor to control the grating setting as it's really easy under kstars/indi.
My usual capture software of choice is to use a raspberry pi at the telescope running kstars/ikos/indi, and remote desktopping to it via VNC.
The SBIG DSS-7 looks like it was a nice unit BUT unfortunately the slit was not a reflective slit and there was no facility for a guide camera to view the front of the slit in order to keep a star on the slit for long exposures. The intent seems to have been for it to be mostly used on extended objects such as nebulae and galaxies. from the user manual:
"The small DC motors in the DSS-7 are powered by a 9 volt battery. The motors are controlled by signals from the CCD camera’s relay port through a phone jack connector. There is no provision for guiding. The length of exposure one can take will be limited by your telescope’s ability to track unguided unless you have another camera set up to work as a guider. For stellar work, it is not easy to keep the star on the narrowest slit. For diffuse objects it is much easier since a little motion still usually leaves some nebulosity passing through the slit. Reasonable spectra of stars as faint as 9th magnitude can be achieved in 30 seconds with an eight inch (20 cm) aperture telescope. Putting the star in one of the wider slits helps, but will yield some blurring of the spectrum. The 100 and 200 micron slits are included mainly for diffuse object observations. "
I'd say if you are willing to spend a lot of money, the shelyak instruments Alpy, uvex and e'shell are all excellent. I took years to get my partly home built and partly commercial system almost fully remote operable, and have enjoyed that. Adding extra servos and relay controls has been quite easy with kstars/ekos/indi by minor scripting of an additional Arduino microcontroller.
I think the biggest battles in operating an amateur spectrograph (excluding a simple Star Analyser transmission grating, although there is some real science use for it also) are:
- achieving a sufficiently high load focuser capacity to reliably focus and remain collimated when carrying multiple cameras and the spectrograph.
- pointing sufficiently accurately to put a target star on the slit
- keeping the target star on the slit. I do like Phd2 BUT it tends to oscillate the target on the slit due to the two clipped edges of the star image each side of the slit. I have been told that Astroart and PRISM do have autoguiding routines can guide on the slit without oscillation.
In terms of buying, the motorised version of the Shelyak Uvex plus their calibration module would include all the motors and interfacing to operate the spectrograph fully remotely. But as Robin says, there's a big difference between remote and automous. Remote meaning the operator is sitting at a remote computer but operating the spectrograph in real time whereas autonomous meaning the operator sets up a run and goes to bed / the movies/ dinner and comes back to see a fully completed observation run.
The main difficulty in getting autonomous operation working is to reliably position the target star on the slit to a precision of less than a pixel, but the position of the slit in the guide camera field of view may move a pixel or two as equipment flexure and/or thermal expansion happens. But not only 2Spot but also some others have achieved this with a combination of scripts and platesolving.
I operate my own equipment set up in the backyard from inside the house via a long permanent ethernet cable, as wifi was a bit unreliable. I have remote operation of the following:
- mount, of course (but manual polar alignment, however I leave the mount set up and protected from weather, and just install the optical tube with all equipment as a single lift at the start of the night)
- remote focus of the telescope
- servo operation of mirror for the calibration lamp, and relay for the calibration arc lamp
- servo operation of a flip mirror to send the telescope output to a large chip camera for platesolving, or direct to the spectrograph.
- guide camera on the spectrograph
- science camera on the spectrograph
- large chip dslr for platesolving. the field of view of the spectrograph camera which views the reflective slit plate is small, the image quality is not the best due to aberrations in the relay optics, and also extra reflections from the uncoated front surface of the slit plate, so platesolving the guide camera image often doesn't work. Hence I capture a platesolving image with the dslr, use the solved position to synchronise the pointing direction, and achieve centering of any coordinates to within less than 10 arcseconds before switching to the guide camera and adjusting the target the final few pixels onto the slit for guiding during the long spectroscopy exposures. I am usually using several exposures of 1200seconds for the target star when at the faint limit of my equipment. Calibration stars are usually circa 60 second exposures at circa magnitude 6.
In a normal night, the only manual operation I have to do at the telescope is to switch on the halogen flat lamp shining at the white wall near the telescope for spectrograph flats.
My L200 spectrograph is set up for low dispersion as I am usually attempting to take spectra of transient objects tend to be faint and also want wide band spectra, mainly because that is what gets listed on the various automatic survey websites (GAIA alerts, ASASSN survey, CBAT etc) more often. As a result, I am almost always leaving my spectrograph grating set for the band from a bit redwards of H alpha, up to around the Hydrogen gamma line, and don't really need remote operation of the grating setting. However, I have recently been thinking about installing an extra stepper motor to control the grating setting as it's really easy under kstars/indi.
My usual capture software of choice is to use a raspberry pi at the telescope running kstars/ikos/indi, and remote desktopping to it via VNC.
The SBIG DSS-7 looks like it was a nice unit BUT unfortunately the slit was not a reflective slit and there was no facility for a guide camera to view the front of the slit in order to keep a star on the slit for long exposures. The intent seems to have been for it to be mostly used on extended objects such as nebulae and galaxies. from the user manual:
"The small DC motors in the DSS-7 are powered by a 9 volt battery. The motors are controlled by signals from the CCD camera’s relay port through a phone jack connector. There is no provision for guiding. The length of exposure one can take will be limited by your telescope’s ability to track unguided unless you have another camera set up to work as a guider. For stellar work, it is not easy to keep the star on the narrowest slit. For diffuse objects it is much easier since a little motion still usually leaves some nebulosity passing through the slit. Reasonable spectra of stars as faint as 9th magnitude can be achieved in 30 seconds with an eight inch (20 cm) aperture telescope. Putting the star in one of the wider slits helps, but will yield some blurring of the spectrum. The 100 and 200 micron slits are included mainly for diffuse object observations. "
I'd say if the price of well-engineered equipment is acceptable for you, the shelyak instruments Alpy, uvex and e'shell are excellent and are probably good value for money, factoring in the TIME it takes to achieve what they have produced. I took years for me to get my partly home built and partly commercial system almost fully remote operable, although it has been a fun and stimulating process on the way. Adding extra servos and relay controls has in the end been relatively easy with kstars/ekos/indi by minor scripting of an additional Arduino microcontroller, although the information wasn't in one place.
I think the biggest battles in operating an amateur spectrograph (excluding a simple Star Analyser transmission grating, although there is some real science use for it also) are:
- achieving a sufficiently high load focuser capacity to reliably focus and remain collimated when carrying multiple cameras and the spectrograph.
- pointing sufficiently accurately to put a target star on the slit
- keeping the target star on the slit. I do like Phd2 BUT it tends to oscillate the target on the slit due to the two clipped edges of the star image each side of the slit. I have been told that Astroart and PRISM do have autoguiding routines can guide on the slit without oscillation.
For anyone interested in remote operation of a spectrograph there is a nice article by Peter Velez in the BAV spectroscopy magazine describing his semi-robotic (fully automatic but less scheduling currently) UVEX setup.
Yes it is possible to set up a remotely operated spectrograph. A good example is the French amateur 2SPOT team who have both a low resolution slit spectrograph and a high resolution echelle spectrograph operating remotely at a telescope farm in Chile. I believe it also operates autonomously (ie acquiring the target automatically) which is quite a bit harder with spectroscopy compared with imaging
https://2spot.org/EN/
https://www.spectro-aras.com/forum/viewtopic.php?f=6&t=3082
My more modest setup is also operated mostly remotely (except for swapping spectrographs and a few manual adjustments) but only over a few tens of metres over wifi from the house
http://www.threehillsobservatory.co.uk/astro/observatory/observatory_C11_LHIRES_feb_2010.jpg
Cheers
Robin
AAVSO also have experience over many years of trying to operate spectrographs remotely (not all of it good as I understand) Arne Henden would probably know more about this
As Robin mentions, it is straightforward to run a spectrograph remotely - it is really no different than having desktop access to the computerized telescope in your backyard. The two main problems are computer control of any adjustment needed in the spectrograph and whether you want fully autonomous operation.
There are several commercial spectrographs that offer computer control, including the UVEX and the SX-spectrograph pro. The FlexSpec-1 spectrograph described in the Society for Astronomical Sciences proceedings, was designed from the beginning for remote operation - but, you have to build it yourself. I've gone that route.
Autonomous control is much harder. You can usually script to change between flat/cal/science spectra for a single object, and programs like PHD2 can guide a target on a slit. Moving between objects and automatically acquiring new targets is a harder challenge. I can't recommend any specific software, as I haven't had a chance to use any of them. I suggest you avoid this step for now, when you are just getting started.
AAVSOnet has several SA200 diffraction gratings in various telescopes, and they work great for low-resolution studies. Even with an R=100 or so, you still have 20x more spectral resolution than with wide-band filters like Johnson/Cousins or Sloan. We have one eShel mounted at OC61, but won't start using it until that telescope finishes its upgrades.
That said, the AAVSO does have one interesting spectrograph - the SBIG DSS-7. This is a low resolution, but fixed in adjustment, spectrograph that was optimized for the ST-7 camera. It has never been used, and it would be nice to experiment with, and once working, put it on an AAVSOnet telescope. Robin, have you ever heard of anyone using one of these?
Arne
Hi Arne,
No I dont know anyone still using a DSS. The SBig DSS and SGS were the only commercial offerings around when started around 2003 but I could not afford one so when the LHIRES kit came out I jumped at the chance. (Oddly SBig got out of that market just at the time amateur interest in spectroscopy was taking off). As Hamish said, the problem with the DSS was than it did not have a built in guider, just a flip mirror so once you flipped the mirror out of the way you were flying blind. The only way to use it on stars rather than extended objects was to use a wide slit, effectively running slitless or defocus the star so exact guiding mattered less. The SGS was much better in that respect as it had a built in guider using SBig's double sensor cameras, a system similar to that adopted by all subsequent instruments.
Cheers
Robin
Arne,
Do you know if the AAVSO still has its old SBIG DSS-7 spectrograph? I hate to think of it going unused. I'm just getting into slit spectroscopy and would enjoy trying out the DSS-7 if AAVSO would ever consider loaning it out for a week or two (I'm an AAVSO member). Do you think that's possible? Thanks for any thoughts on this!
Best regards,
John Harrington
Newton, MA USA
My ultimate goal is to remotely operated a spectrograph in the backyard observatory.
When I looked at the hardware mentioned above it was clear I lacked the spectroscopy knowledge to make decisions about which hardware to purchase.
After a three month hiatus I purchased the Star-Analyser-200 which will be loaded in the 50mm square filter wheel of the CDK17 (FR-6.8 and FL-2934mm) with QHY600MM.
At present, there are too many unknowns for further hardware upgrades. Hopefully in the future things will be clearer.
I have two other instruments that can be dedicated to spectroscopy
- C14 EdgeHD (F-11 and FL-3910mm) w/reducer(FR-7.7 and FL-2737)
- 140mm APO refractor(FR-7.5 and FL-1050mm) w/reducer(FR-5.7 and FL-798)
Thanks
Steve
Steve,
I know of one company that sells a remotely operated spectroscope: Starlight Express (SX Xpress). I have one of their earlier models that is not fully remote.
Their fully remote model allows you to focus, change the range of the spectrograph, and turn on/off the internal calibration lamp. It uses mirrors, not lenses so it can extend into the UV and IR. It also has a built-in Lodestar for tracking.
Please do not take this as an endorsement of their product. I'm still learning how to use it with mixed results. Advertised R value is 2000.
I'm trying to automate my dome in s/w New Mexico so that it can be operated from my home in Virginia. (Also the location of my wife.) Having my shutter cable snap recently didn't help.
From what we could test at 2SPOT, there are 3 spectrographs that can be remotely controlled without any problem. These are 3 of the spectrographs from the Shelyak manufacturer:
- ALPY 600 in low resolution R=600 very stable because very compact. Once set, the spectrograph does not move. You can remote control the calibration lamps (flat lamp and Ar/Ne lamp)
- UVEX : you can choose your resolution with different gratings to have a resolution between 600 and 6000. You can control remotely the internal focus of the spectrograph, the rotation of the grating (thus the desired wavelength range) as well as the flat lamp and the Ar/Ne lamp for the wavelength calibration
- eShel : a spectrograph with a high resolution of R=11000 which allows to have in one time all the wavelengths between 3900 and 7600 Å. It is a fiber optic spectrograph that can be adapted to any kind of telescope between f/6 and f/9
As usual, you can…
Hi Steve,
As usual, you can buy, or you can build.
In terms of buying, the motorised version of the Shelyak Uvex plus their calibration module would include all the motors and interfacing to operate the spectrograph fully remotely. But as Robin says, there's a big difference between remote and automous. Remote meaning the operator is sitting at a remote computer but operating the spectrograph in real time whereas autonomous meaning the operator sets up a run and goes to bed / the movies/ dinner and comes back to see a fully completed observation run.
The main difficulty in getting autonomous operation working is to reliably position the target star on the slit to a precision of less than a pixel, but the position of the slit in the guide camera field of view may move a pixel or two as equipment flexure and/or thermal expansion happens. But not only 2Spot but also some others have achieved this with a combination of scripts and platesolving.
I operate my own equipment set up in the backyard from inside the house via a long permanent ethernet cable, as wifi was a bit unreliable. I have remote operation of the following:
- mount, of course (but manual polar alignment, however I leave the mount set up and protected from weather, and just install the optical tube with all equipment as a single lift at the start of the night)
- remote focus of the telescope
- servo operation of mirror for the calibration lamp, and relay for the calibration arc lamp
- servo operation of a flip mirror to send the telescope output to a large chip camera for platesolving, or direct to the spectrograph.
- guide camera on the spectrograph
- science camera on the spectrograph
- large chip dslr for platesolving. the field of view of the spectrograph camera which views the reflective slit plate is small, the image quality is not the best due to aberrations in the relay optics, and also extra reflections from the uncoated front surface of the slit plate, so platesolving the guide camera image often doesn't work. Hence I capture a platesolving image with the dslr, use the solved position to synchronise the pointing direction, and achieve centering of any coordinates to within less than 10 arcseconds before switching to the guide camera and adjusting the target the final few pixels onto the slit for guiding during the long spectroscopy exposures. I am usually using several exposures of 1200seconds for the target star when at the faint limit of my equipment. Calibration stars are usually circa 60 second exposures at circa magnitude 6.
In a normal night, the only manual operation I have to do at the telescope is to switch on the halogen flat lamp shining at the white wall near the telescope for spectrograph flats.
My L200 spectrograph is set up for low dispersion as I am usually attempting to take spectra of transient objects tend to be faint and also want wide band spectra, mainly because that is what gets listed on the various automatic survey websites (GAIA alerts, ASASSN survey, CBAT etc) more often. As a result, I am almost always leaving my spectrograph grating set for the band from a bit redwards of H alpha, up to around the Hydrogen gamma line, and don't really need remote operation of the grating setting. However, I have recently been thinking about installing an extra stepper motor to control the grating setting as it's really easy under kstars/indi.
My usual capture software of choice is to use a raspberry pi at the telescope running kstars/ikos/indi, and remote desktopping to it via VNC.
The SBIG DSS-7 looks like it was a nice unit BUT unfortunately the slit was not a reflective slit and there was no facility for a guide camera to view the front of the slit in order to keep a star on the slit for long exposures. The intent seems to have been for it to be mostly used on extended objects such as nebulae and galaxies. from the user manual:
"The small DC motors in the DSS-7 are powered by a 9 volt battery. The motors are controlled by signals from the CCD camera’s relay port through a phone jack connector. There is no provision for guiding. The length of exposure one can take will be limited by your telescope’s ability to track unguided unless you have another camera set up to work as a guider. For stellar work, it is not easy to keep the star on the narrowest slit. For diffuse objects it is much easier since a little motion still usually leaves some nebulosity passing through the slit. Reasonable spectra of stars as faint as 9th magnitude can be achieved in 30 seconds with an eight inch (20 cm) aperture telescope. Putting the star in one of the wider slits helps, but will yield some blurring of the spectrum. The 100 and 200 micron slits are included mainly for diffuse object observations. "
I'd say if you are willing to spend a lot of money, the shelyak instruments Alpy, uvex and e'shell are all excellent. I took years to get my partly home built and partly commercial system almost fully remote operable, and have enjoyed that. Adding extra servos and relay controls has been quite easy with kstars/ekos/indi by minor scripting of an additional Arduino microcontroller.
I think the biggest battles in operating an amateur spectrograph (excluding a simple Star Analyser transmission grating, although there is some real science use for it also) are:
- achieving a sufficiently high load focuser capacity to reliably focus and remain collimated when carrying multiple cameras and the spectrograph.
- pointing sufficiently accurately to put a target star on the slit
- keeping the target star on the slit. I do like Phd2 BUT it tends to oscillate the target on the slit due to the two clipped edges of the star image each side of the slit. I have been told that Astroart and PRISM do have autoguiding routines can guide on the slit without oscillation.
As usual, you can…
Hi Steve,
As usual, you can buy, or you can build.
In terms of buying, the motorised version of the Shelyak Uvex plus their calibration module would include all the motors and interfacing to operate the spectrograph fully remotely. But as Robin says, there's a big difference between remote and automous. Remote meaning the operator is sitting at a remote computer but operating the spectrograph in real time whereas autonomous meaning the operator sets up a run and goes to bed / the movies/ dinner and comes back to see a fully completed observation run.
The main difficulty in getting autonomous operation working is to reliably position the target star on the slit to a precision of less than a pixel, but the position of the slit in the guide camera field of view may move a pixel or two as equipment flexure and/or thermal expansion happens. But not only 2Spot but also some others have achieved this with a combination of scripts and platesolving.
I operate my own equipment set up in the backyard from inside the house via a long permanent ethernet cable, as wifi was a bit unreliable. I have remote operation of the following:
- mount, of course (but manual polar alignment, however I leave the mount set up and protected from weather, and just install the optical tube with all equipment as a single lift at the start of the night)
- remote focus of the telescope
- servo operation of mirror for the calibration lamp, and relay for the calibration arc lamp
- servo operation of a flip mirror to send the telescope output to a large chip camera for platesolving, or direct to the spectrograph.
- guide camera on the spectrograph
- science camera on the spectrograph
- large chip dslr for platesolving. the field of view of the spectrograph camera which views the reflective slit plate is small, the image quality is not the best due to aberrations in the relay optics, and also extra reflections from the uncoated front surface of the slit plate, so platesolving the guide camera image often doesn't work. Hence I capture a platesolving image with the dslr, use the solved position to synchronise the pointing direction, and achieve centering of any coordinates to within less than 10 arcseconds before switching to the guide camera and adjusting the target the final few pixels onto the slit for guiding during the long spectroscopy exposures. I am usually using several exposures of 1200seconds for the target star when at the faint limit of my equipment. Calibration stars are usually circa 60 second exposures at circa magnitude 6.
In a normal night, the only manual operation I have to do at the telescope is to switch on the halogen flat lamp shining at the white wall near the telescope for spectrograph flats.
My L200 spectrograph is set up for low dispersion as I am usually attempting to take spectra of transient objects tend to be faint and also want wide band spectra, mainly because that is what gets listed on the various automatic survey websites (GAIA alerts, ASASSN survey, CBAT etc) more often. As a result, I am almost always leaving my spectrograph grating set for the band from a bit redwards of H alpha, up to around the Hydrogen gamma line, and don't really need remote operation of the grating setting. However, I have recently been thinking about installing an extra stepper motor to control the grating setting as it's really easy under kstars/indi.
My usual capture software of choice is to use a raspberry pi at the telescope running kstars/ikos/indi, and remote desktopping to it via VNC.
The SBIG DSS-7 looks like it was a nice unit BUT unfortunately the slit was not a reflective slit and there was no facility for a guide camera to view the front of the slit in order to keep a star on the slit for long exposures. The intent seems to have been for it to be mostly used on extended objects such as nebulae and galaxies. from the user manual:
"The small DC motors in the DSS-7 are powered by a 9 volt battery. The motors are controlled by signals from the CCD camera’s relay port through a phone jack connector. There is no provision for guiding. The length of exposure one can take will be limited by your telescope’s ability to track unguided unless you have another camera set up to work as a guider. For stellar work, it is not easy to keep the star on the narrowest slit. For diffuse objects it is much easier since a little motion still usually leaves some nebulosity passing through the slit. Reasonable spectra of stars as faint as 9th magnitude can be achieved in 30 seconds with an eight inch (20 cm) aperture telescope. Putting the star in one of the wider slits helps, but will yield some blurring of the spectrum. The 100 and 200 micron slits are included mainly for diffuse object observations. "
I'd say if the price of well-engineered equipment is acceptable for you, the shelyak instruments Alpy, uvex and e'shell are excellent and are probably good value for money, factoring in the TIME it takes to achieve what they have produced. I took years for me to get my partly home built and partly commercial system almost fully remote operable, although it has been a fun and stimulating process on the way. Adding extra servos and relay controls has in the end been relatively easy with kstars/ekos/indi by minor scripting of an additional Arduino microcontroller, although the information wasn't in one place.
I think the biggest battles in operating an amateur spectrograph (excluding a simple Star Analyser transmission grating, although there is some real science use for it also) are:
- achieving a sufficiently high load focuser capacity to reliably focus and remain collimated when carrying multiple cameras and the spectrograph.
- pointing sufficiently accurately to put a target star on the slit
- keeping the target star on the slit. I do like Phd2 BUT it tends to oscillate the target on the slit due to the two clipped edges of the star image each side of the slit. I have been told that Astroart and PRISM do have autoguiding routines can guide on the slit without oscillation.
For anyone interested in remote operation of a spectrograph there is a nice article by Peter Velez in the BAV spectroscopy magazine describing his semi-robotic (fully automatic but less scheduling currently) UVEX setup.
https://bav-astro.eu/images/BAV_13-2023.pdf
Cheers
Robin