Re: Should I record a PEM?

Christopher Erickson

Roland and Ray will certainly give you the best and most useful answers but I'll throw in my two cents because I am in a sharing mood right now.

On lights of exceptionally-bad seeing, I have experimented with PEM training runs, just for fun and self-teaching.

My experience has been that running about 7 to 10 worm turns results in pretty good and even excellent PEM training, in spite of the bad seeing. Exactly like combining a lot of subs to minimize noise. This success is certainly partly due to how smooth the RA worm gears and wheels are my Mach1 and 1100. Cheaper mounts with sharper changes in periodic and random tracking errors might not give the same good results. Make that WILL not give the same good results. LOL

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738

On Mon, Jun 29, 2020, 11:37 AM Mojo Jones <mojo@...> wrote:
I'm successfully using APPM in the early evening to map 23 points or so. I have to say, not having the autoguider makes everything so much more reliable and fast. There's no need to "plate solve and center" on a new target -- it's always center of the frame in SGP. I'm also in a very forgiving system with a wide field and old camera.

I'm sorry I didn't buy APCC Pro back when I had a discount offer with a new 1100GTO. I didn't think it would serve any purpose when I'm not in a fixed observatory. I was very wrong!

I've been shooting a Messier survey from home in Los Angeles County. Not because my shots are interesting or especially good, but because I can. :) Doing this has given me tons of experience with the entire process from set up  to final image processing, by repeating it frequently. I've captured 47 Messier objects in the past two months, about 30 minutes of imaging time on each, with an old one-shot color SBIG camera.

I have two setups: My small system is a very old (first run) Mach1 GTO with an AP Traveler 105mm f/6. The big beast is an 1100GTO with an AP 180EDT. I haven't been using the big one so often because taking it down involves waking up my wife at 2:30 to come out and help me lift it off the rings and stow it. She's been very willing for the most part, but I save that for special occasions.

The Mach1 has a few enhancements, like the updated Alt-Az base, and adapter for the RAPAS scope. I've upgraded the CP3 to the V2 chip, so it works beautifully with APCC Pro. It does NOT have levers to disengage the drives from the gears, so I'm not able to do a delicate balance on the Mach1. But the system is light enough that it doesn't seem to be critical.

Since I upgraded my CP3 controller chip, I've been running with PEC OFF.

Finally my question: This system is very forgiving, with a huge wide field, and 2.45 arc-seconds per pixel. That's a little bit high compared to the recommendations for recording a PE curve in PEMpro.

Should I bother?

Best regards,
Morris Jones, Monrovia, CA
Old Town Sidewalk Astronomers
Mojo's Blog   

Join to automatically receive all group messages.