Instrumentation and Equipment

I've only been doing CCD photometry for around 10 months so I'm still on the learning curve.  Based on my reading, I've always thought that guiding was not that critical for differential photometry.  If the stars are slightly out of round, it doesn't matter as long as all the light fits into a reasonably sized aperture.

However, I was just looking at Dennis Conti's "A Practical Guide to Exoplanet Observing" (https://astrodennis.com/Guide.pdf) and he seems to indicate guiding is critical for the accurate results needed to measure a transit.

I've recently obtained M67 data from a system consisting of a CDK20, QHY268M camera, and Baader BVRI filters.  The B filter does not have a red leak, based on V838 Mon data.  However, I'm a bit disappointed in the transformation coefficients, as calculated by TG.

Tb_bv = 0.211

Tv_bv = -0.017

Tr_vi = -0.130

Ti_vi = -0.051

Tbv = 1.269

Tvr = 1.242

Tri = 0.868

Tvi = 1.037

with typical fitting errors around 0.01 from 3 independent calculations of the coefficients.

     This paper appeared on the astro-ph preprint server last week:

https://arxiv.org/abs/2302.03700

Scientific CMOS sensors in Astronomy: QHY600 and QHY411

...which details linearity tests, dark current, etc from lab and on-sky tests.  Lightcurves of an asteroid and of an exoplanet transit are displayed.

\Brian

Súper newbie here,

and here I am, another Astroimager taking the plunge; and looking for some low hanging fruit.

Please don’t judge!

Can I use Nina , in  any extent for capturing data?

They came up with a new plug-in regarding EXO planets that can come up with variable and comparable stars.

Can I use Pixinsight, on any extent, to process, calibrate, and maybe even measure a curve?

my equipment

2 TOA150eat with an ASA 6200 MM with Narrowband and broadband filters.

Hello

If anyone would like the graphs and photos from this article, just email me via the contact here or attempt this URL:

(1) Measurement of Photometric Filters | LinkedIn

New photometric filters were purchased. Some photometric filters had been reported as having out of band leaks. I wanted to measure the actual response of my filters.

I've been doing BV photometry for a few years now and recently moved on to adding R and I.  But I'm finding that with the I filter only, I'm getting many negative pixels in my calibrated images (SBIG ST8XME).  What's the best way to handle this, add an offset to my raw science images before applying darks and flats?  It would only take about 30-50 ADU.

Keith

     Hardware folks may find the following report of interest, which appeared on the astro-ph preprint server last week:

https://arxiv.org/abs/2211.04913

StarDICE I: sensor calibration bench and absolute photometric calibration of a Sony IMX411 sensor

Betoule et al, accepted for publication in A&A

\Brian

Hello! After I've moved to eastern Tennessee, at a location that is limited by tall trees in the horizon and lots of nights with clouds, I miss being able to image at a site that has more clear nights.

    Does the AAVSO sponsor a site that members could pay for/manage  to host their equipment (or are others interested in sharing the costs for a site)? I've looked at a number of sites, though most of them are expensive since they cater to astrophotographers rather than photometrists.

Hi,

  I'm new to AAVSO. I've been doing astrophotography for about 2 years now, but have been an amateur visual astronomer for a long time. I want to start using my equipment for variable star photometry in addition to deep sky imaging. 

Hello! I just set up my Meade LX200 Classic telescope in humid east Tennessee after moving from dry southern New Mexico. I've never had to deal with such dew before!

    I've been looking dew controllers.

    For those of you with SCTs who use dew control strips - do you put a strip around the corrector plate AND the primary mirror, or just the corrector plate?

    Is a small strip useful on the tube where the CCD connects to the telescope back as well? Thank you and best regards.

Mike