Image Train Advice Please

[Honitonman]

I have a SM90 EDT, Adjustable Flattener, Filter Holder, ASI 585 and a 120mini for guiding all on an AM5 mount.  I have used this rig for the last 3 months to successfully image a number of Nebula so no problems with Back Focus .  Now that the planetrs are back again I thought I would use my 4x (2") Powermate to increase the magnification so that I could image Saturn, Jupiter and Mars.  I was advised to remove the flattener and replace it with the Powermate with the Camera directly attached to the Powernate using the 42mm T-ring adapter. However I cannot get focus, I must be doing something wrong or the advice I was given was incorrect, HELP!!!

[Elp]

I assume you're using a diagonal first?

Scope > diagonal > PM > camera.

4x is also quite extensive, you may be beyond your scopes max mag, I never went more than 3x with a refractor imaging planets.

Edited August 3 by Elp

[bosun21]

You will probably need to fit an extension in between the powermate and camera. Your scope is f6 and the pixel size is 2.9 so a 2.5x barlow is much better suited. For average seeing you want roughly 5 x pixel size which is just under 15 so a 2.5x is bang on. You could also use a 2x barlow. You can use the ROI to increase the planets size on the screen. A 90mm scope is not a good choice for planetary imaging due to the small aperture.

[Elp]

4 minutes ago, bosun21 said:

A 90mm scope is not a good choice for planetary imaging due to the small aperture

It's still possible, I've done it with reasonable results with my Z61, but sure, it won't match the resolution of my C6.

Edited August 3 by Elp

[Honitonman]

Hi Guys,  thanks very much for the advice, I also have a 2x barlow so may give that a go instead. I primarily bought the 90 as my first foray into imaging and I have been delighted with the results for Galaxies and Nebulae.  I tried Saturn the other night and could just make out the planet sphere with the rings on either side, was hoping that I could do a little better using the Powermate but there you go.

@Elp   I wasn't going through the diagonal, but will give that a try also just to see whether I can achieve anything that way

[symmetal]

With my refractor and the 4x Powermate I had to add an 8cm 2" extender and rack the focuser out another 2cm to reach focus. 🙂

Alan

[900SL]

My 90mm requires around 80mm of extension tubes if I remove the field flattener 

 

[michael8554]

Remove the camera and focus the landscape onto a wall behind the OTA.

That will give you an idea of where the camera sensor should be placed.

If the landscape image is too dim, briefly try the sun.

Michael

[bosun21]

10 hours ago, Elp said:

It's still possible, I've done it with reasonable results with my Z61, but sure, it won't match the resolution of my C6.

Yes it's also possible with a 50mm but still not a good choice.

[bosun21]

9 hours ago, Honitonman said:

I tried Saturn the other night and could just make out the planet sphere with the rings on either side, was hoping that I could do a little better using the Powermate but there you go.

Did you use the ROI to increase the planets size on the screen?

[Honitonman]

@Bosun21  As per the title of this thread I am still very new to imaging and am threading my way through a huge intake of information as I get to grips with various components and software.  On my initial attempt with just the flattener I was not using video so didn't even think about ROI.  The SM90 is my only telescope so may not be a great choice for planetary imaging, but thought I would give it a go with the 4x Powermate anyway.  I do appreciate your help and advice

@Michael8554  I will give that idea a try today and see what I get. Thank You

@900SL and @symmetal  it sounds as though 80mm may be the way to go will see if that correlates with the wall test. Thank you 

[Elp]

For what it's worth, these are some of my first APs with my 60mm, so with your 90mm you'll get a better result:

[bosun21]

15 minutes ago, Honitonman said:

@Bosun21  As per the title of this thread I am still very new to imaging and am threading my way through a huge intake of information as I get to grips with various components and software.  On my initial attempt with just the flattener I was not using video so didn't even think about ROI.  The SM90 is my only telescope so may not be a great choice for planetary imaging, but thought I would give it a go with the 4x Powermate anyway.  I do appreciate your help and advice

@Michael8554  I will give that idea a try today and see what I get. Thank You

@900SL and @symmetal  it sounds as though 80mm may be the way to go will see if that correlates with the wall test. Thank you 

I'm not saying don't use your 90mm but you shouldn't expect too much. Video is the way to go for the planets with as high a frame rate you can achieve. Using the ROI will increase the frame rate and make the target larger on screen. This is lucky imaging which allows you to select the sharpest frames captured for stacking. Good luck.

[Elp]

You can use image capture also at high frame rate if the capture software allows, this was/is my preferred method because once the images are captured they're "safe" and already written to storage. Video can artifact and sometimes corrupt though I've never had it happen (artifacting has happened however). Either option is fine, whatever works for you.

[Honitonman]

Guys you are great, thanks so much for your advice and guidance,  as of right now anything bigger than a pin head with a line through it would be welcome 🤣.  I will be trying it with the diagonal as recommended by Elp later today. Cheers

[Bivanus]

Well, I can only tell you how it went for me: no diagonal , just a series of extenders that helped me find the sweet spot. Also , if you have one, maybe try with a 2x Barlow first ? The 4x is already tricky. And yes , as other coleagues already let you know: for planets filming is the way 🙂

[Honitonman]

ELP's recommendation has worked for me.  I achieved focus using an eyepiece in the barlow to start with and then replaced it with the camera.  Thanks for all the advice and help guys 🙂 👍