Jump to content


Photo

CGEM at lower latitudes?

  • Please log in to reply
11 replies to this topic

#1 P-Dub

P-Dub

    Sputnik

  • -----
  • Posts: 26
  • Joined: 30 Dec 2011

Posted 07 December 2012 - 02:03 AM

My wife and I have just been stationed in Guam. I have a CGEM and the lower limit of the mounts Lat adjustment is 15 deg. Guam is located @ approximately 13.45. I want to still be able to use the mount for astrophotography but we all can see the problem :confused:. Any suggestions?

#2 RTLR 12

RTLR 12

    Aurora

  • *****
  • Posts: 4558
  • Joined: 04 Dec 2008
  • Loc: The Great Pacific NorthWest

Posted 07 December 2012 - 02:22 AM

Adjust the legs on the tripod to align the mount to the latitudes below 15ยบ. Just be careful of tipping of the mount.

Stan

#3 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5452
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 07 December 2012 - 09:26 AM

put a brick under one leg of the tripod.

since I live at 1.22 degrees latitude, the brick trick didn't work for me, so -

Posted Image

The above solution was nice, but the solid CNC machined wedge is quite heavy and it wasn't cheap to have made. So for my other mount I had a different wedge fabricated which is made from four aluminum plates bolted together.

Much lighter, and it doesn't seem to be weaker.

Posted Image

#4 Raginar

Raginar

    Fly Me to the Moon

  • *****
  • Posts: 6138
  • Joined: 19 Oct 2010
  • Loc: Rapid CIty, SD

Posted 07 December 2012 - 10:21 AM

I agree, get a wedge madde before you go. A couple of hundred for a wedge to use your CGEM is worth it.

:jump:

#5 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5452
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 07 December 2012 - 11:18 AM

If you're interested in my wedge design, I can send it.

#6 P-Dub

P-Dub

    Sputnik

  • -----
  • Posts: 26
  • Joined: 30 Dec 2011

Posted 07 December 2012 - 08:04 PM

@orlyandico, Would love it. We are actually here already so I have to get one or make one myself. I'll shoot you a PM. Thanks for the input and suggestions all.

#7 zinsco1

zinsco1

    Lift Off

  • -----
  • Posts: 21
  • Joined: 27 Dec 2009

Posted 08 December 2012 - 11:50 AM

Greeting and welcome to Guam, since polaris is not in view here. Drift align is the way to happiness. On my cgem i have the longer counter weight bar. And micrometered the marks on the lat scale and simply scibed a couple of additional( since the lat adjustment does run by the 15 degree mark this got me about 14 to 13.9 or so and i was in businness.Then i use a compass to set north Litte advice make sure your equipment is moble and able to get under cover quickly as the rains here do come rather unexpextly. otherwise the viewing here is pretty good Nice dark skies particulary on the north end of the island. zinsco1

#8 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5452
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 08 December 2012 - 11:55 AM

err.. why not use the ASPA?

i just started using the ASPA on my CGEM here in Singapore. it works great, actually. Better alignment than I ever did with drift alignment.

#9 P-Dub

P-Dub

    Sputnik

  • -----
  • Posts: 26
  • Joined: 30 Dec 2011

Posted 08 December 2012 - 09:31 PM

Thanks zinsco1. Do you astrophoto here? Would love to hook up sometime. Unfortunately it looks as though we are going to be stuck south in Santa Rita, just up the hill from Big Navy, and since I plan on doing astrophoto hope it gets dark enough. Good tip on the weather. I do believe that ASPA should work, yes? Just hope that it'll all align and track well enough for photos.

#10 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5452
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 08 December 2012 - 10:09 PM

if you're using the CGEM unguided, the massive periodic error will make your life miserable. Still with 30-60 second exposures at most.

if you have access to an autoguider, much better... the PEC routine can cut the PE in half, allowing you to double your unguided exposures.

but really, at a really dark site, 60-second subs will show plenty, just use lots of them.

#11 P-Dub

P-Dub

    Sputnik

  • -----
  • Posts: 26
  • Joined: 30 Dec 2011

Posted 09 December 2012 - 04:45 PM

I guide so that shouldn't be too much of an issue. Thanks for the heads up.

#12 zinsco1

zinsco1

    Lift Off

  • -----
  • Posts: 21
  • Joined: 27 Dec 2009

Posted 10 December 2012 - 02:24 PM

Hey P-DUB yea i attempted a foray into astrophoto, thats how i got the lesson on the weather i had eyes on the laptop and equipmnt didnt notice the big nasty cloud and bamn torential downpour scambled to save equipmennt but lost my ccd / guide camera and the laptop. saved mount annd main scope. With regards to ASPA or drift align whichever you can set up faster as the power grid here is less than stellar and does drop off unexpectedly, Running a/c adapters is the only way to power all the equipment. A/C to D/C connverters nnot readily availible here and cost a small fortune to ship if they will ship. And make sure all your A/C stuff is GFI connected either by cord or outlet. Send me a PM and we can connect, i live in a great area for dark skies and have really nice nirghbors who turh off their yard lights when i have my gear set up. zinsco1






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics