Help with planetary imaging

[BJunge]

Hi, I live on the Gold Coast and want to do planetary imaging from my backyard but want some advice on whic 1.25" filters to purchase. My gear is...

1. Celestron Edge HD 9.25
2. ZWO 290mc
3. Az-EQ6 mount

I have been doing some reading and seems aperture of 300mm or more is desired, I have (234mm'ish) and if influences which IR pass to buy. Also which planet you are targeting requires a different IR pass bandwidth. I was also further confused when coming across Red + IR pass filter (R + IR), are they the same as a IR pass, totally different or two filters stacked.

So my question is, which IR Pass or R+IR Pass filter/s is/are best to purchase? I am sold on Baader UV Pass, just would like the advice of those with far more experience and expertise!

Many thanks for your time!


Clear skies,


Brendan.

[Startrek]

You can image planets with just about anything but focal length and aperture, focal ratio play a bit part together with atmospheric conditions
I’ve produced some of best planetary images on my 6” f6 newt a DSLR and 5 x Powermate

Here’s some relevant info I put together to work our focal ratio for my current rigs

Focal Ratio for Lunar and Planetary Imaging

General rule of thumb to determine the best focal ratio of your image train for Lunar and Planetary imaging is -
Average night of seeing 5 x pixel size of your camera
Good night of seeing 7 x pixel size of your camera
Canon 600D pixel size is 4.3 uM
Average seeing 4.3 x 5 = 21.5
So focal ratio F21.5
Good seeing 4.3 x 7 = 30.1
So focal ratio F30.1
6”f6 Bintel scope use 4 x or 5 x powermate
8”f5 Bintel scope 4 x or 5 x powermate

Also some images taken last year with both 6” and 8” scopes

I don’t use filters, and these were imaged under Bortle 8 light polluted inner suburban skies

Recommend 2 programs, Autostakkert 3 for stacking and Registax 6 for sharpening and colour

Cheers

[rustigsmed]

with the camera you have, which is colour, i'm not sure you require any filters. IR and UV etc are usually done on mono cameras. so you're good to go as is :thumbsup: perhaps if anything a simple CCD light pollution filter will be fine for you.

[glend]

Yes on the Gold Coast, a good light pollution filter is a good idea.

[foc]

Hi,

With your ZWO I290mc color cam you need a UV/IR blocker (or images will be a little blurry and color off) and just use a normal luminance channel in Fire capture, stack in Autostakkert3! and tweak wavelets in Registax 6.

IR bypass filters can sometimes improve detail in poor seeing but if seeing is reasonable it is best not to use them on the planets.
For the planets or Jupiter I doubt you will get much benefit from an light pollution filter. I mage in Canberra and do not use one, and know of few others that do so for the planets.

Seeing and (with Cats/Maks tube currents and collimation) are the issues that affects the quality of images in the planets most often. Seeing may be a lot better where you are and tube currents may also be less of an issue if you keep the scope outside. I have not got as good images with my standard C8 and 2.5x powermate on its Celestron Evolution mount so far in April this year as I did in earlier in March for the planets (see March images below) when they were more distant as I have not had good seeing when I have got up early.

Saturn is much fainter than Mars or Jupiter and needs better seeing conditions than I have had while this far from opposition and so is by far the worst of the three images. I do have many far better images of Saturn but this one illustrates how it can look in a C8 in poor seeing at the moment. At present I am capturing Saturn at around 30fps compared to 200fps for Mars with a ZWO I224MC. But judging from last year where I was using a C6 as we get close to opposition (in July for Saturn and Jupiter), I know I will get images much better than these early images from this year.

[rustigsmed]

yes a lot of people don't use light pollution filters when planetary imaging however the 'ccd' versions have UV/IR cut in them as well which is why i mentioned it.

[Camelopardalis]

Brendan, I’ve seen some excellent images taken with a C9.25.

R+IR would be something like the Baader R610...has a wide bandpass so shouldn’t block out too much light.

To keep your expectations real, start out at f/10, and then try a 2x Barlow. Doesn’t need to be a fancy one given the size of the sensor in the 290. Ideally, f/15 is the sweet spot for it, but 1.5x Barlows are (at first glance) uncommon. Unscrewing the lens itself off a generic lens and moving the glass closer to the sensor shorten the multiplier.

And, as you will already have heard, good seeing is the biggest determinant (along with good collimation and focus) on what you will get. Good luck!

[BJunge]

Thank you for all of your feedback. I also have an ASI174 Mono mini guider, can this be used for planetary imaging?

One another note, if I purchase a UV pass filter for Venus it can only be used with a mono camera? Can it also be used for deep sky imaging of nebula, galaxies etc.?


Thanks again for all of your insights!

[Saturnine]

Hi Brendan
Your camera and scope are perfectly suited for planetary imaging, you will need an UV / IR Cut filter but you wont need a light pollution filter, the planets and moon are bright enough to easily see from LP skies. What you will need for nights of steady seeing is an 2X Barlow, Televue Powermates are favoured by most planetary imagers in this regard. That will give you plenty of focal length, for Mars especially though your scopes native focal length of 2350 mm is fine for getting good images on less than perfect nights.
I use the same camera as yours, the ZWO290mc with UV / IR filter on an 150mm F8 Saxon Newt on an HEQ5 mount, moving up in aperture this year though and a 2.5 Powermate for the planets and the moon sometimes. So I'm imaging at 3000mm focal length, which is a bit much for the aperture and pixel size but in good seeing the results are worth it. Some examples from last year attached.

Have Fun

[rustigsmed]

re: 174mm mini ,yes it will work for although it is usb2 so you won't be able to get ultra high fps that you could with a usb 3. but still not a major issue in good seeing. not many people use uv filters - most will use them for Venus only. sometimes a UV and near IR bicolour works well for a coloured Venus.

there is some info on the useage on the baader page https://www.baader-planetarium.com/en/filters/baader-u-filter-(venus-and-uv---350nm).html

[foc]

I seem to recall that UV unlike IR (and hence the earlier references in other posts to the option of IR filters rather than very the cheap UV/IR blocker), is often taken out by glass or other materials in the imaging train and so you need specialized arrangements to capture it. If you want the crescent shape of Venus then normal lucky imaging with a normal IR (and usually UV) blocking filter should give you that, with the main challenge being Venus sinking early at this time of the year in Australia. For chasing cloud formations and the associated cheap/expensive filter options you might be best looking to the solar system imaging thread in Cloudynights.com, there is a great of recent informative Venus imaging posts there from experts.