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I picked up an older CG-5 mount and tripod the other day for $50. It's in good shape, just a bit dirty. The Dec axis moves freely with the clutch loosened, and drives very smoothly with the clutch tight. The RA axis drives very smoothly with the clutch tightened (bear in mind this is a totally manual mount), but is stiff to move with the clutch loosened, and has a couple of spots where it is very slightly "notchy" when it is turned. How can I loosen this up, to make hand-skewing to a target easier? It has no polar scope, no big deal, and has provisions to add tracking motors, but I doubt I'll do that. I bought it to have a simple, grab-and-go mount to throw the frac or C6 on to look at the moon, etc. It's usable as-is, it tracks nicely with the worm drive, but I'd like to get it back to its "former nights of glory" condition.
I think it may be as simple as re-greasing the bearings, but I'm not sure what I need to do to take it apart. There is a collar that has two small holes for a tool like a circlip plier, located underneath the RA setting circle ring (at the bottom, where you'd insert a polar scope), looks like that has to come out to break the RA bearings apart.
An unexpectedly short EAA session on the night of January 18 led to only one capture... it would have been longer but for the clouds, and I seem to have a problem with star shapes.
This is from my Quattro 8", successfully used before, but with a new (to me) camera and imaging train. Here's a 20 second sub as captured on screen (Nebulosity) and then a post-processed image with 22 of them stacked (for a total of 7 minutes, 20 seconds)
The problem, though, is with the star shapes:
The image train is:
Coma Corrector (previously used and absolutely fine) ZWO OAG (new for Christmas, but not in use yet, except as a spacer) Baader variable spacer Atik 460EX mono CCD cooled to -12C (this is 'Gina-cam', thanks @Gina!) Everything is threaded connections, I don't think it's tilt, and it doesn't look like a classic CC spacing issue. This is unguided, and certainly the PA wasn't perfect, but collimation was (I believe) good. The OAG prism was way out of the way from the long-side of the chip, so my hope is that this might be caused by the high wind that night? (Mount is an Avalon M-Uno.)
Any suggestions/advice? I will, of course, be trying again in better conditions, if they ever arrive.
I have a Celestron 8" with CG-5 Mount that I purchase about 14 years go. I have not really used it much since due to family and work pressures but as I am close to retirement I am re kindling my interest in Astronomy. Over the years I have lost the polar scope an have been attempting to purchase a new one. My local astronomy shop had what looks to be the correct one in stock bit it would not fit. I Tried both the CG4 and CG5 polar scopes but the tube is too wide. The polar scope for my old mount must be thinner than the later ones. I have contacted Celestron but they can't help. Does anyone know what the problem is or where I might obtain one for the older mount. If not are there any other methods for performing polar alignment without using the polar scope. I have heard of some software that does this but only with GT mounts. I would eventually like to do some astrophotography but it appears that polar alignment is critical for good results.
I've previously posted a bicolour version of IC 410 but the other night I managed to captured some SII data so what follows is a Ha / OIII / SII narrowband rendition of the Tadpoles.
Usual set-up for this kind of thing (CG-5 mount, Atik 460ex, Atik OAG / IMGOH / PHD), but the Ha was captured with both my TS90APO and FSQ-85.
Ha 25 x 600s
OIII 23 x 600s
SII 29 x 600s
The different fields of view from the twio scopes were reconclied in RegiStar, stacked in DSS and processed in AstroArt 5 and PhotoPlus X4.
The first of these is what dropped out of the processing, the socond has had the stars tamed by blending in a layer that has had teh AA erosion routine applied. Then followed endless tinkering to try to get the result to look okay on SGL! I've no idea why but images that look fine on my desk top take on a green or magenta hue when posted on here. Maybe part of thr problem is that I don't really like to leave the sky really black as I don't think it looks natural... but on this one I've gone pretty dark!
Hope you like it! I feel like I've got some good data here; in fact I think that this is the first time I've had decent data for all three channels. It probably has more to give but I am pleased with this .
Thanks for looking.
Higher quality version of the above here.
Higher quality version of the above here.