Dear Forumers,
Currently I am waiting for my 14" high-quality mirror from Rik ter Horst, which would be the optics for my planetary newton in the future. I want to use the scope in the next years from Tenerife (a friend has a flat there with big balcony which I can use for free, so I only have to pay travel expenses).
This project will be minimum another 1 year to accomplish, and I really miss astronomy these days. My main problem is I live in Budapest, capital of Hungary which has 2 million inhabitants - and because of my dialy schedule I cannot go out to observe during nights. I have a small balcony on the 6th floor in the middle of the city, so I can really say that circumstances are horrible, seeing because of warm air among houses, light pollution all makes it hard to do planetary, even solar images.
As I was always interested in doing more than just "pretty images" as you say and to do something with science, I checked double and variable stars as an option. I would be interested in CCD or DSLR photometry, but as my balcony is very-very small, circumstances are bad, and I have a tight budget, I am not sure it is even possible to do quality work. I know some of you might say I should start with binocular and visual estimates, but to be honest I am not interested on that at all, I was always a photography guy even in the past, when I did a lot of planetary work.
So to summarize, I would like to ask this:
1. Is it possible to do observing from my terrible balcony (I only see a small portion of the sky to the South, so even objects are limited)? Most of the nights I can only see the brightest stars.
2. What is the smallest scope size / type that is already enough to be part of AAVSO alerts?
3. What tpye of CCD / DSLR do you recommend to use? I want to go with the cheapest possible option, as I would only do this for variables, so I believe no fancy things needed.
4. If there are any other type of projects that can be done from a "balcony with a small scope", I would be interested to hear about them - so far variable starts seemed to be the only option.
Thank you in advance,
Gabor
Hi Gabor,
Yes, you can certainly do good photometry from a city, it's my case. I am in the heart of the Dijon city in France and do a lot of photometry and some spectro from my terrace on the top of a building. By chance I can see, let say, 2/3 of the sky from that place. I can see the other 1/3 from a window I have equipped with a small astro-photo mount (the Star Advanturer).
2- Size of the scope: I would say any ! That depends on the target, a simple tele lens ~ 200mm F/4 is able of good photometry from mag 3 to about mag 9 (like an old Nikkor F that costs $ 100 and is adaptable to Canon DSLR). We have discribed that case in:
https://www.aavso.org/apps/jaavso/article/2879/
A small astro-photo mount is perfect for such operation, it's even possible to work with a mount without tracking or even a simple tripod in case of bright stars.
Then larger aperture provides access to fainter stars, accurate photometry is possible at mag 11~12 with a low cost 8" Newton. A survey at lower precision is possible at such mag with a 200 mm F/2.8 tele lens. It's all a question of mag-precision combination being needed.
3- A "recent" low end DSLR is perfect for such work, it provides tri-color data that can open lot of possibilities not presently exploited by most observers ! Recent CMOS APS-C sensors are superb performers: low instrumental noise, very very low dark current, high electron storage capacity in small pixel (said well depth in CCD world), very linear up to saturation, 14 bits RAW... What is important is the camera has the full software and interface to be controlled by computer for time series, this is the case of Canon and Nikon DSLR (but not all non-DSLR). Some other brand have it or not depending the type, it's to be checked on case by case basis.
Next it's better the camera uses a RAW coding with a systematic offset that allows for some negative values (background extraction in noise issue). Canon is the case, not Nikon, others ?
4- You can do spectroscopy too, starting with a simple SA100 at low cost. Number of spectroscopists work in cities, one well known observes from the center of Paris ! But planetary work is also possible, remember one of the most famous planetary guy observes from his balcony in an asian city !
Clear Skies !
Roger
Hi Gabor, Your situation does indeed sound very challenging! Given your very poor conditions, I would say CCD would be the better way to go anyway, because binoculars or small telescope visually under extremely light polluted conditions will be very frustrating. It will be hard to even locate objects if you cannot see the proper star patterns under a normal sky. CCD's do surprisingly well even when the background is bright.
But, if your sky is so much blocked by buildings that very little can be seen, maybe the best option is just consider relocating to a better site! Now, I understand that may not be possible in some circumstances, say if you own the flat, but if you can move, then finding a better spot even nearby in a better part of the city may be best.
Light pollution can vary much within a city. It depends more on the immediate lighting in the area surrounding you. For example, if you can find a location adjacent to a large body of water, a park or green area, or on side of the city which faces your preferred observing direction, which has mostly farms and fields that way, your conditions would be much improved.
So, I would recommend looking for better sites with characteristics I mention, which are still conveniently located for your work and transportation.
Mike
Dear Gabor,
Thank you for your comments and welcome to the AAVSO observer family! I understand the challenges you face; I too come from a big city where light/sky pollution is a big issue. At the same time, you don’t need “perfect” skies for variable star observing. I will not repeat the excellent suggestions by colleagues in this forum. Here’s a couple of additional comments:
1) You could consider observing from the rooftop of your building IF you have access to it – it would give you access to a larger portion of the night sky
2) Have you considered solar observing? You may need a solar filter (white light) for your telescope, and we can discuss this if it is of interest
3) The AAVSO provides manuals for new observers for visual/DSLR/CCD observing which are easy to follow, and can be found here: https://www.aavso.org/observing-manuals We offer workshops (CHOICE courses ) on various topics; perhaps one of them can be of interest to you? The 2016 schedule is listed here: https://www.aavso.org/2016-choice-course-schedule
Once you decide to join the AAVSO as a member, you will have access to our mentoring program, and have a mentor who can help you with your observing.
I hope this helps. Please feel free to contact us – we are here to help! I am looking forward to receiving your data!
Best wishes – clear skies,
Stella.
There should be
Kedves Gabor!
There should be several mentors in Hungary, since your country is very strong on variables - I used to subscribe to the Hungarian periodical 'Albireo' (which is why I started to learn Hungarian). The AAVSO has several active members in and around Budapest. But I have to agree with the member who suggested that you simply relocate. I did, purely for astronomy.
Gabor,
You might want to consider using one of the on-line rental telescope networks. I think there are several of these. When you consider the cost of new equipment as well as the hassles and limitations of observing from a balcony in a large city, this cost might be worth it to you. I once met a gentleman at a meeting who was a very active amateur scientific observer who did all his observing this way.
At least one of these networks offers reduced rates during lunar bright time. This would be a good option when you're learning to do photometry. I think it may also be possible to have your images uploaded directly into an AAVSO VPhot account.
For photometry you would want to ask the telescope provider about their photometric filters and how often they refresh their flats and transforms.
Phil
I would agree with Phil. I
I would agree with Phil. I use remote telescopes when the cold winter nights make outdoor viewing with either my 250 mm Dobsonian or 120 mm Refractor a bit uncomfortable. I use VPhot at AAVSO to help me process my digital images with consistently excellent results. It is very easy to do with good tutorials to help you out. I can also reach 18th magnitude variables so you can really expand your viewing experience. I have been using Sierra Stars Observatory Network (SSON) Dave