Adam AP Mach 1, Rob Miller TRI36L, Celestron 8" Edge HD Hyperion 17mm, Celestron 40mm Plossl, TMB 7mm & 9mm WO 66, Lunt LS60/B1200 PT, CG-5 Clone STF-8300m Pro Package, Honis-Modified Canon XS, Un-modded T1i, SSAG, TSOAG9, SX LodestarLackawanna Astronomical SocietyMy Astrobin
Others may disagree. Your millage may vary. Void where prohibited by law.
Quote:When using the polar alignment scope, it is necessary to assure that the polar alignment reticle is centered on the mount's polar axis.
I lost count of my scopes. Now I just want mobility. I came, I saw, I bought some interesting accessories, and put names to faces: NEAF 2012, ASAE 2012, SWAP 2013, ASAE 2013.
Quote: When using drift alignment, it is necessary to make sure that cone error is eliminated, i.e., that the OTA's optical axis is parallel to the mount's polar axis. If both of these conditions are true, the polar alignment scope method and the drift alignment method will agree perfectly, assuming both methods are executed perfectly.
http://www.astrobin.com/users/orion69/ TS 150 mm APO Triplet, Feather Touch 3.5" focuser, Micro Touch Focusing System CGEM on custom made platform Atik 383L+ mono, Atik filter wheel, Baader LRGBC + narrowband filters SX Lodestar + TSOAG9 Dew-Not heater
Quote:I am wondering, though. After you finish a drift alignment, how far does Polaris typically move from where it should be in the polar scope? Is it just slightly off from where it should be or is it possible that it will be as much as half the FOV away in the PA scope?
Terry Danks Photography: Birds, Scenery, a little astrophotography too. http://danks.netfirms.com/home.htm Equipment List: Too embarrassed to list it all. Roll-off-roof Observatory Constructed Fall, 2013
Quote:OTA's optical axis doesn't have to be parallel to the mount's polar axis or to be precise doesn't have to be dead on (but usually it's close enough), it's maybe easier to do drift alignment if optical and mount polar axis are parallel.
Quote:Also, you'll match precision of good drift alignment with polar scope only if you're very,very lucky, in fact never.
Quote:The conclusion was that you should NOT rotate the PAS within the polar axis housing after centering the reticle. Instead you adjust for HA by rotating the entire PA, NOT just the PAS.
Quote:Quote:The conclusion was that you should NOT rotate the PAS within the polar axis housing after centering the reticle. Instead you adjust for HA by rotating the entire PA, NOT just the PAS.A-P Mach1 mount is different than others. Rotating the RA axis does NOT rotate the PAS. That's how they designed it. So A-P had to make the PAS rotatable and they did not do a good job because it does not rotate in perfect circle. No matter how well the reticule is centered, rotating PAS to match the Polaris' Hour Angle is necessary but also causes the reticule to be off center.Peter
Quote:The thing I found hard about the AP polar scope was that when you turn the reticle to align the stars it seems to loosen up and become more sloppy depending on where you need it to be. I finally gave up and use the scope just to get a rough sighting of Polaris in the scope. It's then usually close enough that the quick drift align goes faster. I put my name on the list for the new Polar scope just because it's such a clever idea.
Quote:I cannot align PAS to the mount because rotating Mach1 RA axis does NOT rotate PAS. I would need to get get something like a V-Block and position PAS on the V-Block to see if the reticule is centered but I chose not to do it because I didn't really feel like it and PAS is never intended for accurate polar alignment for imaging. It's a good tool if you go to a dark site and allows you to get pretty close so that Drift Alignment would be faster.I tried to find a link to A-P PAS for Mach1 about why Mach1 RA axis will NOT rotate PAS but it's not there. I believe the main reason for this design is to allow "through-the-mount-cabling" otherwise the cables will get all twisted. A-P Mach1 is a fantastic mount and polar alignment is very easy. Just read the manual.Peter
Quote:My project for the week is to adapt a T-thread to the polarscope of my EQ6 (removal of the eyepiece is obviously necessary). Hopefully the PS has enough aperture for my lodestar to pick up several stars. If it can I plan on using astrometry.net to solve the image and overlay the image with a crosshair where NCP is. In theory all I'd need to do is place the NCP at the image centre. I have no idea how well this will work however...
http://www.faintfuzzy.net Stuff C14, C8, Orion XX14i, Meade 8" ACF, AT6RC, AT102ED, Orion ED80, PST, AP1600GTO, CGE, CG5, ST10-XME/CFW8, QHY8PRO, Optec TCF-s, Microtouch Focuser, Pyxis LE, Hyperstar for C8.
Quote:Quote:My project for the week is to adapt a T-thread to the polarscope of my EQ6 (removal of the eyepiece is obviously necessary). Hopefully the PS has enough aperture for my lodestar to pick up several stars. If it can I plan on using astrometry.net to solve the image and overlay the image with a crosshair where NCP is. In theory all I'd need to do is place the NCP at the image centre. I have no idea how well this will work however... I know of someone whose normal polar alignment routine is similar to this. Instead of a PAS and guide camera, he just uses his regular imaging camera in the main OTA. With the mount aligned near the NCP, he takes an exposure for a few seconds. During the exposure (with the RA clutch released), he rotates the RA axis 180 degrees.This gives him an image where Polaris transcribes a 180 degree circle in the field. He moves the mount such that the semicircle is centered on the center of the camera's field.He claims that this works well for him and that he never has a problem with drift or field rotation.
Quote:I really hope the new right angle finder scope from AP is as good as the TAK.
Tak-106, AP900GTO, Unitrons, Masuyamas
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A-P Mach1 on 12" concrete pier - ROR structure.
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