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Two questions if I may.
1. Can the three screws marked by yellow arrows in the picture below be used to mount a second finder shoe on the C11 EDGE HD scope, permitting both a straight through and a right angle finder to be fitted?
2. The EDGE has field flattening optics inside; is the distance from the visual back to the chip critical, or by making adjustments to the position of the mirror to achieve focus on a chip say 250mm away from the visual back mean the field will still be flat at that distance?
bit of a long post coming up in stages but I thought I'd share this as it may help out others.
A few weeks ago while I was packing away my kit I noticed that the leg clamps on my Celestron CPC tripod had cracks in them right where they join the spreader.
Two had cracks right the way through & one was halfway through. I hadn't noticed this before but have no idea how long they had been like this.
Very thankful that I spotted it before they completely gave way & my tripod collapsed with my scope etc still mounted.
Hi gang, I have a small issue with my CPC & need some information from other CPC owners.
Basically I was having a look at the Fastar connection for Hyperstar but noticed that the whole Secondary assembly was a little loose & could be rotated on its own leaving the corrector plate securely fixed.
Here’s where I made my first mistake, I lost track of the original starting position of the assembly but it didn’t end there.
The only way to tighten the assembly & stop it rotating freely the corrector plate needs to be removed as the Secondary unit is tightened on the underside of the corrector.
Next mistake, I forgot to mark the corrector position to aid refitting, not considering the fact that it’s position would be important on reassembly.
Turns out that my corrector has no significant markings on it except in 2 places on the edge, about 45° apart are an arrow pointing to the outer face & the number 4.
Through much head scratching & the use of digital calipers I think I have found the correct orientation of the corrector plate in order to reassemble but I am still stuck with not knowing the correct position of the Secondary assembly.
I have read various articles that contradict each other stating that one of the 3 collimating screws should be at 12o’clock or 6o’clock.
What I have noticed though is that when the outer retaining ring is unscrewed from the Secondary assembly, there is a small locating grub screw that sits within a slot on the assembly housing, see pic:
a big ask I know but is it possible for other CPC owners, mine being a 9.25” if it matters, to unscrew the Secondary retaining ring & note the position, on a clock face (top of OTA as 12), of this locating slot. It would be much appreciated.
I know there’s plenty of discussion pertaining to Primary & Correctors as marching sets, although from what I gather this was for earlier SCT models, plus 365 Astronomy lists the corrector as a replacement part: https://www.365astronomy.com/Celestron-C9.25-Replacement-Corrector-Plate-50984-1S.html
so I’m hopeful that nowadays the matched pair issue is not relevant & ive got away with my stupid mistake.
for the time being while away from home I have been using my car's own battery to power my setup but last time out I noticed some curious happenings & only recently have put it down to what I think is a power issue.
I had setup my equipment as usual & my scope seemed to be tracking just lovely. I got a bit chilly & decided to sit in my car for a while to warm up with the engine running & heater on.
After some time and slightly warmer I switched the ignition off, left my car & took a peek through my scope, it was way off target. At this time I didn't associate this error with a power issue.
Once again, started and achieved alignment, scope was tracking beautifully for a long while, again, after getting cold again I did the same as before and got in my car, started it up and sat there to get warm. Some time passed.
Upon checking the scope again, again it was off target. By this time the sky was getting light & I didn't want to bother starting a new alignment procedure so I packed up.
It wasn't really until I got home that it dawned on me that the process of me starting my car whilst my equipment was connected directly to the battery could have been the cause for the tracking glitches.
I understand that the process of starting a car alters the voltage in the battery and I am wondering if this either drop off or surge in voltage disrupted the tracking of my scope. Could this be the case?
So anyway, I have decided to build a field power pack but just want to clarify some details with you brainy lot.
12V x 1.5A = 18W (i'll allow 20W) info from: http://www.rothervalleyoptics.co.uk/celestron-cpc-925-xlt-telescope.html
INPUT 19V x 2.37A = 45W
OUTPUT 14.8V x 2520MAH = 37.3WH
estimate of power need through normal 6hr battery life (( 45 x ( 37.3 / 45 )) / 6 ) = 6.2W
INPUT 8V x 3A = 24W
OUTPUT 7.2V x 1040MAH = 7.49WH
estimate of power need through normal 4hr battery life (( 24 x ( 7.49 / 24 )) / 4 ) = 1.9W
DEW HEATERS (ASTROZAP)
1 x SCT9.25 12V x 1.3A = 15.6W
2 x 1.25" 12V x 0.25A each = 6W total
1 x 2" 12V x 0.35A = 4.2W
So far I calculate a total of 54W per hour or allowing for a 12 hour stint 648W total
I was also wondering if I need to factor in my ZWOASI224MC camera which runs via USB3 on my laptop & also my Flat Panel Maker, which runs via regular USB power?
That said, I have been considering these batteries: https://www.amazon.co.uk/dp/B00XNC7KZ0
which are a pair of 12v 33AH AGM Scooter batteries which should allow a total of 792W which should cover my needs.
Do all my above calculations look OK?
Do I need to place any type of voltage regulator between the batteries and the outlet?