SVBony SV305C Proper Attachment and Focusing

[SahRobbie]

I recently purchased the SV305C to use as an electronic viewing eyepiece and also capture images on my Celestron 8SE. This is my first attempt at using an astronomical camera. I have successfully connected the camera to my laptop and it is recognized and accessible in SharpCap 4.1. However, I have been unable to focus on any object or view anything other than total black or blindingly bright images in SharpCap. I have exhaustively experimented with Exposure, Gain, White Balance, and other settings to no avail.

I first attached the SV305C unit to the Celestron Star Diagonal, then directly to the Visual Back, then to the Visual Back via the Barlow Lens - none of which have allowed me to focus on any object, day or night. I have even ordered the SV305 version thinking that perhaps the SV305C does not work with SharpCap 4.1, or that I may have received a defective unit.

Can anyone advise me on the proper way to attach the SV305C unit to the Celestron 8SE and then focus the image in SharpCap? I am at a complete loss at this point. I have searched the forums but did not find any topics/info specific to the SV305C and Celestron 8SE. Any help would be immensely appreciated!

Sarah

[admin]

Hi Sarah,

it's very likely that your camera is fine, but you are hitting the hardest part of astrophotography - getting the very first image.

To get a good image on the screen, you need to get all of these right at the same time:

* Have the right settings for the camera (exposure, gain, etc)
* Have the telescope pointing at something (not just blank, dark sky)
* Have the focuser in the right position (which will be different to the one for eyepieces)

If you start trying with the night sky, then you tend to get a black image if any of these are wrong, so getting all three right at once is hard...

I would suggest the following approach

* Set up in daylight, pointing the telescope at a distant object on the skyline (tree, house roof, etc) - use an eyepiece to confirm that the center of view is not just the sky - it has something with some detail/contrast in it
* Replace the eyepiece with the camera and connect to laptop/PC
* Open SharpCap, then open the camera with the <CTRL> key pressed down - this stops SharpCap from reloading the last used camera settings, so that any changes you made while experimenting are reset to defaults
* If you see a black image, turn up gain and or exposure to get a mid brightness image. If you see a white image, turn those down to get a mid brightness image. Try to avoid exposures longer than about 100ms so that the image on screen updates relatively quickly
* Once you have a mid brightness image, you have a chance of seeing some detail when you get the focus right.
* Now adjust focus to try to get an in-focus image of the tree/roof/whatever that the telescope is pointing at. The camera will see a much smaller area than the eyepiece - this is why we wanted something that is not just grey sky in the center when setting up.
* Adjusting focus is particularly tricky on SCTs as you have to make lots of turns of the focus knob, and it is hard to know which direction
* If you really struggle, move the telescope up/down - you should see the transition between the brighter sky and the darker ground as the telescope moves between them - make sure that you end up on the 'ground' side of the divide for further focus testing

Once you have an image of a tree/chimney pot/roof sorted on the camera, the next easiest target is the moon. Ideally leave the camera on the telescope and do not change the focus that you had for the distant object - that won't be perfect for the moon, but it won't be too far out. The advantage of the moon is that it usually has a glow around it, so if your telescope isn't quite pointing right at the moon, you can still see the glow by turning the exposure/gain up a bit. Then you move the telescope to make the glow in the image brighter and know you are closing in on the moon itself...

Hope this helps,

Robin

[SahRobbie]

Thank you so much for the detailed reply, Robin. I have spent hours attempting to filter through online info to get this sorted, so I am very grateful for your help!

Having read other suggestions online, I actually had tried focusing on a distant daytime object (after first lining up the view with the eyepiece), but could only see black in the SharpCap Live View. I will try again today but will be sure to use the CTRL key method to reset the camera settings as you suggested.

Would you also be able to tell me what the best position is for attaching the camera unit to my Celestron 8SE? Should it be inserted into the Star Diagonal or the Visual Back?

Thank you again so very much!
Sarah

[turfpit]

Sarah

My first scope was a Celestron 6SE, I used the camera straight out of the visual back.

My first object was Saturn, it took me 3 nights to get the planet to appear in the field of view of the camera. Things will improve with practice. The daytime setup is the secret.

Dave

[SahRobbie]

Hi Dave,

Thanks for the encouragement! I have placed my camera in the Visual Back as well - glad to know it's in the proper location, thanks! I'm thrilled to have had success today in attaining a recognizable and focused daytime image thanks to Robin's guidance. Woohoo!! Next goal is a moonshot.

I was also able to install and set up the ASCOM Platform & appropriate drivers to get Scope Controls working within SharpCap. Definitely some forward progress today. Looking forward to getting my focus motor set up so that all mount and scope controls are within SharpCap. What a great piece of software it is. Time to support the developers and purchase the Pro version, even though I'm sure any additional Pro version controls are well beyond my abilities.

Best,
Sarah

[turfpit]

Thanks Sarah. Look in
https://www.google.com/search?sca_esv=3 ... 04&bih=838

Any documents with a title starting with HOWTO are going to be useful to you soon.

Good luck.

Dave

[turfpit]

Sarah

Found the first image I captured back in November 2016 - Celestron 6SE scope + NexImage 2 camera + iCap capture software

saturn.PNG

8 years later viewtopic.php?t=7344


Dave

[admin]

Hi,

you should be able to place the camera in either the visual back or the diagonal, since the SCT has a really wide range of adjustment on the focus. I think you will find the focus adjustment needed between the eyepiece and the camera smaller if you use the diagonal, but not 100% sure.

If you are stuck at an all black image, turn up the exposure and gain and (if needed) shine a torch into the telescope - you should be able to get the image to lighten up that way. Then you can cover the aperture and check it goes dark again, verifying that your camera is responding to light/dark properly.

cheers,

Robin

[SahRobbie]

Thanks for the pic, Dave! I'm impressed you were able to get a Saturn image in just 3 days. I'm sure it will take me quite a bit longer, but if I do manage it I'll be sure to post a pic.

Cheers,
Sarah