How much (if any) cropping did you do? And I take it that without the coma corrector, the images not as sharp - particularly towards the edges? If it is cropped, could I twist your arm into posting a full frame 60s shot? (I have the K50 and would like something a little faster than my ED80 7.5 to shoot through so the Bintel F4 is pretty tempting).
Very nice Kevin, but I sort of disagree with Hoges; any half decent 8"
fast Newt will produce that result. The credit goes to Kevin's
processing skills, and the coma corrector. I can produce the same amount
of detail with a bit more exposure time with my 8" f/5, but the final
result is nowhere near as good as Kevin's because my processing skills are almost non existent, and I use JPEGs because I find using RAW too
difficult.
raymo
The credit goes to Kevin's
processing skills, and the coma corrector.
Hey, no argument from me there I'm pleasantly surprised to see a fast and relatively cheap newt can make images that good - in the right hands of course. Also, I've never used a coma corrector so don't know much about them.
Also, I've never used a coma corrector so don't know much about them.
You can see how much coma ruins the images from my 6" F/5. Kevin's F/4 would be even more affected (by a decent margin) if it wasn't for the CC. I really need one, but I'm hoping that at F/5 I can get away with a cheaper one from GSO.
You can see how much coma ruins the images from my 6" F/5. Kevin's F/4 would be even more affected (by a decent margin) if it wasn't for the CC. I really need one, but I'm hoping that at F/5 I can get away with a cheaper one from GSO.
I assume you're referring to the slightly elongated stars either side of your M42 photo compared to Kevin's? Still pretty darn good though and I certainly wouldn't use the term 'ruins'!
How much (if any) cropping did you do? And I take it that without the coma corrector, the images not as sharp - particularly towards the edges? If it is cropped, could I twist your arm into posting a full frame 60s shot?
Hi John. I cropped very little. Only a few pixels off the edges as I dither subs and there was some overlap. What you see is 99% of the total. Here's a single 30 second frame without any cropping for comparison.
These F4 scopes are unusable without a coma corrector. They are essential for reducing edge coma. I reckon the Baader MKIII does a pretty good job. Sorry, no pic of M42 without the coma corrector. Next time I'm out there I'll get one, but bad weather has set in for a while by the looks.
Many thanks Kevin. Even with the price of the Baader included, it looks like a lot of bang for the buck to me. And to get that much detail out of a 30 second exposure.....can you imagine what astro imagers would have given for that capability in the 80's? I'm sure I've got a Jack Newton book on astro images from the early 80's somewhere....
I used to shoot film back in the 1980's and 90's. Long exposures, manual tracking with a reticle eyepiece on the OAG or guidescope. Ray is an old timer film astrophotographer too.
I remember Jack Newton's photos in Astronomy magazine from the 1980's. I think he was the fellow that used cold cameras? He obtained beautiful results.
8" F4 Bintel Newtonian, 9 x 60 seconds unguided, a few shorter subs of 8 seconds for the core, mostly at ISO 400, Pentax K-5.
Can you go into a bit more detail? There's a lot of equipment on your sig and I'm not sure what mount you used and any other doohickeys.
Seriously, so I could get an 8" Newt on an AZEQ6 and get results like this with a DSLR?! If so then why does everyone say to get a 10x more expensive ED80/120 APO and guiding camera/scope for another $500 on top instead?!
Can you go into a bit more detail? There's a lot of equipment on your sig and I'm not sure what mount you used and any other doohickeys.
Seriously, so I could get an 8" Newt on an AZEQ6 and get results like this with a DSLR?! If so then why does everyone say to get a 10x more expensive ED80/120 APO and guiding camera/scope for another $500 on top instead?!
Hi Cody, mount was an HEQ5 pro. Subs were unguided. On the plus side, at the time of taking this image M42 was near the meridian. My sky in that direction is fairly dark in spite of having many street lights to the west. On the minus side, air temp was very warm, near 30C adding some noise to the subs. I used flat frames but not dark frames for this image. I also used a Baader UV / IR cut filter inline. It can help cut through haze a little better. The Pentax K-5 is an off the shelf unmodified camera with no cooling.
I also have an ED100 Refractor. It will do a similar job but take longer to do it. Fast fat Newts are a good combination with a DSLR.
I haven't set the guidescope up on the Newt yet. Not much point in summer as longer subs just get noisy from the heat. I might get around to it when the weather is cooler and I want to go deeper.
Strewth these F4 Newts are fast. Good thing too since getting 9 minutes here in summer is hard to get. 
I'm pleasantly surprised to see a fast and relatively cheap newt can make images that good - in the right hands of course. Also, I've never used a coma corrector so don't know much about them.
