5 replies to this topic

[Fernando Alonso Velez]

Recently, I begin to preparate an equipment thinkng to do photometry, and following the AVSSO tutorial is posible to do this even with a DSLR camera and small lenses, however I like use a refractor APO (~4') with a focal lenght about 700mm, but I wolud like to know about experiences doing photometry with this OTAs. Some question that I've are:
Is necesary an refractor APO? or acromatic is enogh?
Is a  6' RC a better option?
I thank your sugggestion and comments

[pbealo]

An achromat is fine, APO will work just fine as well.

 

More aperture will allow imaging fainter stars. But 4" is fine. "Use what you have".

 

Peter B.

[Ed Wiley]

Fernando,

 

Have a look at https://www.aavso.org/aavsonet-history and you will see that AAVSO has been using small scopes extensively to monitor bright stars. Even a 60mm refractor (or 50mm for that matter) is useful, all you have to do is pick appropriate stars. Many of the brighter stars of interest are too bright for larger scopes and are under-observed. Also, note that you don't need an expensive camera.. I use a 183-chip based cooled mono CMOS with BVI on my 3" refractor.

 

Ed

[Jamey L Jenkins]

You may want to take a look at my article in the June, 2023 issue of the Astronomical League's Reflector magazine.

 

Downloadable from here:  https://www.astroleague.org/reflector/

 

I use a 102mm f/7 ED refractor for photometry of LPVs, nova, and a few Young Stellar Objects. I've found this instrument suitable for targets from about 8th magnitude down to 14th magnitude in V.  For brighter targets I use a medium focus camera lens mated with a CCD camera identical as used on the refractor.

[Xilman]

Recently, I begin to preparate an equipment thinkng to do photometry, and following the AVSSO tutorial is posible to do this even with a DSLR camera and small lenses, however I like use a refractor APO (~4') with a focal lenght about 700mm, but I wolud like to know about experiences doing photometry with this OTAs. Some question that I've are:
Is necesary an refractor APO? or acromatic is enogh?
Is a  6' RC a better option?
I thank your sugggestion and comments

Anything is fine. It's not how big it is that's important, it's what you do with it.

 

I started my VS observations with a 5mm (0.2 inch) refractor which had lousy chromatic aberration, astigmatism and didn't focus properly. The camera was unfiltered, uncooled and had a bad signal to noise ratio. It still made useful measurements.

 

It was a Mark-1 eyeball.

 

Learn to use what you have before investing serious money in other stuff. I am quite certain that you can make scientifically valuable measurements with a little education, care, and attention to detail.

[jgraham]

+1

Use what you have. I have used a wide variety of telescopes, mounts, and cameras and they have all worked well. I kinda like having about a 1 degree field of view, but even that is negotiable. I have used my RC8 with a Baader Mk III MPCC and a Canon EOS Ra and that worked well. I am currently testing a Seestar S50 and the initial results are very encouraging!

Enjoy!