Some Astrophotography Questions

Started by hdlsparky, 10/14/2005 04:51PM
Posted 10/14/2005 04:51PM | Edited 10/17/2005 12:00AM Opening Post
Good morning all smile

I'm always eager to admire the wonderful posts on my daily stop here at Astromart. I have posted here occasionally in the past, but I am always in awe of what the backyard amateur is capable of these days. My questions are as follows:

Firstly, I am interested in knowing what the best sub-exposure times for various types of images would be. i.e. It is apparent that good images require a lot of data, not uncommon to have 90 or 120 minutes luminance + Ha alone. From your experiences, what would the best sub-exposure times for the variuos types of objects be? (i.e. 10, 15, 20 minutes, etc.). Clearly, the longer the sub-exposure, the greater the risk of vibration degrading the image, etc.

Secondly, for imaging deep sky objects when there is a bit of haze caused by light pollution and the like, what would the best filter be? What are the best RGB and Ha filters?

Thirdly, I have a 14" LX200GPS that yields beautiful images visually. I have seen some pretty spectacular images on this website, but many are using some fairly high-end equipment - AP1200 and Millunium mounts, AP155's, etc, etc. Could somebody direct me to some really fine images taken using a Meade 14" LX200GPS? I am considering the purchase of an STL-11000, in hopes of getting some decent images, but I would first like to know if anyone has used an STL-11000 with a Meade 14" LX200GPS taken with the standard Meade mount. I don't want to invest the money in a fine CCD if the telescope is not up to the task. I have posted a quick image of M57 I took a couple of years ago using my 14" LX200GPS with a Meade 416XTE, unguided, no wedge, 5 X 30 second exposures for each LRGB (I suppose this would translate to LRGB 2.5:2.5:2.5:2.5 for a total exposure of a whopping 10 minutes).

Sorry for the long-winded post, but I'm looking forward to some expert advice.

Clears skies all.

Thanks for reading,
Derrick.
Edmonton, Alberta, Canada smile

Attached Image:

hdlsparky's attachment for post 27474
Posted 10/14/2005 09:32PM #1
Well Derrick ,seems like you know more than you think you know. It's been trial and error for everyone on here I'm sure and that surely includes me. Learning your scope/camera combo will teach you what sub exposures you need. Object looks too dim, increase the exposure. Object is burnt out, decrease the exposures. Some things just have too many variables to give a straight answer.
As far as filters. I don't think anyone could live in a more light polluted sky than me. I don't use any LP filters. Long exposures, good flats and a lot of processing gives me decent results.
Now for your scope. I think that most people who decided to start imaging, has had some sort of LX200. They are good scopes but unless you have a really good one, they are limited by some tracking issues. With the one I had, I always ended up with football shaped stars no matter what I did. I like football but not in my images.
The ST11K is the premier CCD camera. If your serious about imaging, go for it. Although, I'd try something a little smaller first. See how your scope performs and later if you're liking what your getting then upgrade.