Hi,
I have a question that may be embarrassing, but here goes any way. First of all I have a new mount, camera, filter wheel and optical tube ordered (3 month wait...ugh). I am trying to plan ahead and was looking at the back focus requirements for the new camera, etc. etc. The new telescope is an Celestron EdgeHD SCT, I mainly do photometry, the diagrams for the new camera were showing the camera attached straight through the telescope for showing the back focus distance. That makes the image reversed and inverted. SO that got me to thinking...
I have always used the diagonal with my current camera (very small and light) so that the images are only reversed. To be honest about it I never really thought about before, but...Is that the right way? Is there a better way? My concern is the new camera and filter wheel will be too heavy for this configuration. Is there a way to generate a star chart that is reversed AND inverted so I can easily match it to the image taken WITHOUT the diagonal?
Darrell
Darrell,
You don't need worry about this type of image orientation. With your imaging software usually you can flip, flop, rotate, mirror reverse your image any way you like when you display it. This is not necessary when making the photometry measurements, but it may help you when you examine the images prior to doing the photometry.
Just connect your camera directly to the back of your SCT with the proper adapter. I most cases this is a "SCT" (female) to T-thread (male) adapter. This is stronger and more stable than using a 1.25 inch or 2 inch "nose" screwed into the the camera (or FW) T thread. Sometimes a spacer may also be required, but probably not in this case.
Phil
Hi Phil,
I took a look at the software I use for photometry, Muniwin 2.1, and it doesn't have the options to change the image orientation. Looks like I have to have the chart match the image. So it looks like Barbra's got the right idea for getting North and East in the "right" direction on the chart depending on which side of the meridian I an imaging.
Thanks for your suggestion though, I'll keep it in mind, it still may come in handy.
Darrell
In VSP, you can just request the orientation that you need. You can request N up or down and East to the left or right. For my 16” SCT with no diagonal on a GE mount: imaging east of meridian gives me an image that is south up and east to the left. If I am imaging west of the meridian then north is up and east is to the right. I just request a chart for whatever side of the meridian I am on.
Barbara
Thanks for answering…
Hi,
Thanks for answering. Yes, I understand now. I also need to sharpen my chart matching skills. ;) I knew the answer was going to be in front of my face. The reason I was using the diagonal was the pointing accuracy of my mount is poor and I would have to get the target in the very center of the FOV to get an image because of the size of the CCD on my camera, so I would have to do fine adjustments by hand to get my image. I needed the image to match what I was seeing so I would know how to move the tube. The new mount (CGX) and camera (ZWO ASI294MM) with a bigger sensor should help with that.
Holy moly a 16" SCT! Nice.
Darrell
> The new mount (CGX) and camera (ZWO ASI294MM) with a bigger sensor should help with that.
With the new mount and canera, you might want to consider making precision pointings automartically via platesolving. So you tell the mount where to point, the first try will be a bit off, you push a button in the acquisition software like SharpCap, it takes a frame, calculates the actual current pointing coordinates via a third party , free plate solving software, it then tells your mount to correct the pointing accordingly and voila, the desired coordinates are dead in the center of your frame, no manual intervention needed whatsoever.
P.S.: have fun with the 294mm pro, I have that one as well and like it quite a lot.
Cheers
HB
Hi,
Thanks for your suggestion. Yes I do plan on using plate solving to help point the mount. I am using Astro Photography Tool and All Sky Plate Solver, I believe I have everything configured for that to happen as soon as the new mount and camera get here. The first piece of the new imaging system arrived yesterday, the new guide scope, I could do something with that, but of course it's forecast to be cloudy here for the next week. Just waiting and waiting...
Darrell