20 replies to this topic

[ordnance11]

I just purchased a Celestron Edge 8HD. I plan to use a ZWO ASI678MC planetary color camera. I'

m new at astrophotography.My question is if a filter would be desirable or not? I've used filters for visual observation and it works well. I don't think it's necessary since you can adjust the RGB channels on sharpcap. Any advice is welcomed.

[Tapio]

I have same camera and only use IR pass filter (IR Pro) sometimes.
It helps tame atmospheric problems. Downside is that it makes monochromatic image.

[RedLionNJ]

I just purchased a Celestron Edge 8HD. I plan to use a ZWO ASI678MC planetary color camera. I'

m new at astrophotography.My question is if a filter would be desirable or not? I've used filters for visual observation and it works well. I don't think it's necessary since you can adjust the RGB channels on sharpcap. Any advice is welcomed.

A filter is not only desirable, it is mandatory with the asi678mc.  The bayer matrix transmits equally through all three colors in the near-IR wavelength range, significantly "muddying" the color information received.

 

To avoid this, you need an IR-cut filter somewhere in the optical path prior to the camera.

[ordnance11]

A filter is not only desirable, it is mandatory with the asi678mc.  The bayer matrix transmits equally through all three colors in the near-IR wavelength range, significantly "muddying" the color information received.

 

To avoid this, you need an IR-cut filter somewhere in the optical path prior to the camera.

Thanks for the info.

 

That does kill my plan to just mate the #93644 T -adapter to the camera nose piece. Edge 8 back focus is 133.5 mm. 78.35+ 55 mm -=133.35 mm

 

So that means I need to place a filter drawer in between. I'll have to create an imaging train: Tell me if this checks out and If I need to replace/add anything:

 

Baader 1.25" CMOS Optimized UV/IR Cut Luminance Filter

 

ZWO Gen 2 M42 x 0.75 Filter Drawer for 2" Filters - 21mm

 

ZWO 2" to 1.25" Filter Adapter Ring for Filter Wheels and Drawers

 

Baader Deluxe Short SCT T-Adapter - 15mm

 

Baader Varilock T2 extension Tube 29-46 mm. I can extend it to 42.5 and that brings me in focal lenght.

 

Do I need an M42 to M48 adapter?

[Tapio]

Forgot the UV/IR filter.

This is also possible:
https://agenaastro.c...-t2-1-25-3.html

In planetary imaging back focus is not so critical, imo.

[ordnance11]

Forgot the UV/IR filter.

This is also possible:
https://agenaastro.c...-t2-1-25-3.html

In planetary imaging back focus is not so critical, imo.

Yeah, the high point geat expert just told to just drop the camera into the diagonal. and the camera already have a IR pass coating. So no need to come up with a train, It'll be just overkill. So what does that adapter do?

 

Edit NVM, I found out what it does. Allows me to place the filter directly on the window. I'll give it a shot.

Edited by ordnance11, 11 November 2024 - 11:30 AM.

[RedLionNJ]

Yeah, the high point geat expert just told to just drop the camera into the diagonal. and the camera already have a IR pass coating. So no need to come up with a train, It'll be just overkill. So what does that adapter do?

 

Edit NVM, I found out what it does. Allows me to place the filter directly on the window. I'll give it a shot.

I have my doubts about your High Point so-called 'expert'.  Apparently he or she even has trouble reading their own web page.  Here is the wavelength transmission graph they provide on the asi678mc page:

 

 

So you tell me, how would an IR-pass coating prevent near-IR wavelengths from all three color filters from reaching the sensor and what would you expect the outcome at around 800+ nm to be?

 

 

I'm also sure the majority of experienced planetary images would NOT recommend an unnecessary diagonal in the imaging train.

[Tapio]

https://bbs.zwoastro...on-for-asi678mc

[Tulloch]

Thanks for the info.

 

That does kill my plan to just mate the #93644 T -adapter to the camera nose piece. Edge 8 back focus is 133.5 mm. 78.35+ 55 mm -=133.35 mm

 

So that means I need to place a filter drawer in between. I'll have to create an imaging train: Tell me if this checks out and If I need to replace/add anything:

 

Baader 1.25" CMOS Optimized UV/IR Cut Luminance Filter

 

ZWO Gen 2 M42 x 0.75 Filter Drawer for 2" Filters - 21mm

 

ZWO 2" to 1.25" Filter Adapter Ring for Filter Wheels and Drawers

 

Baader Deluxe Short SCT T-Adapter - 15mm

 

Baader Varilock T2 extension Tube 29-46 mm. I can extend it to 42.5 and that brings me in focal lenght.

 

Do I need an M42 to M48 adapter?

You are making this far too complicated. Here's what you need.

 

1. A 1.25" IR-cut filter, screwed into the nosepiece of the ASI678MC

2. Poke the ASI678MC nosepiece into the 1.25" Visual Back.

3. Start imaging. That's it.

 

Read the Planetary AP FAQ at the top of the page (or linked to below). You don't have to worry about back focus, filter wheels or anything else. You should however seriously consider an ADC (see Sec 6.4 of the FAQ for why).

https://www.cloudyni...september-2024/

 

Andrew

[ordnance11]

I think I see the reason why the gear "expert" said just drop it on the diagonal. That's what the picture on the manual implies: p. 5

 

 

Thanks for the link this should be enough to get me started. The ADC will definitely proof useful since it's a 90 minute drive to where I normally observe and I can't stay long, especially it's take me an hour to set up and break down. Cutting the dispersion helps immensely.

Edited by ordnance11, 11 November 2024 - 06:47 PM.

[Tulloch]

Thanks for the link this should be enough to get me started. The ADC will definitely proof useful since it's a 90 minute drive to where I normally observe and I can't stay long, especially it's take me an hour to set up and break down. Cutting the dispersion helps immensely.

Why do you have to drive so far? You don't need dark skies to image (or observe) the planets...

[ordnance11]

I live in a major city. Bortlier 9 sky. Aligning is going to be hard to impossible. The only starts you can see is near the zenith. Miserable LOS in my back yard. I can go to a park, but same problem with all the buildings around. You also have to share the park with people playing sports and do you really want an errant ball hitting you or your equipment? There's also the case of interesting people you don't want to meet in a dark alley approaching you and "casually" asking how much is all that equipment worth.

[Lacaille]

I’m wondering what mount you have? The Celestron mounts mostly have a “solar system align” routine- get a planet in the eyepiece and just align. No need for two or more targets. This will generally give good enough tracking for planetary imaging.

Regards

Mark

[bunyon]

Can’t speak to bad guys, though there are far fewer out there than thought, but I image planets ~30 feet from a streetlight.

[lajoswinkler]

A filter is not only desirable, it is mandatory with the asi678mc.  The bayer matrix transmits equally through all three colors in the near-IR wavelength range, significantly "muddying" the color information received.

 

To avoid this, you need an IR-cut filter somewhere in the optical path prior to the camera.

Doesn't that camera already have an IR/UV cut filter window? I thought all ZWO's cameras had them. I had to remove mine.

[Tapio]

Doesn't that camera already have an IR/UV cut filter window? I thought all ZWO's cameras had them. I had to remove mine.

No, see the link I posted earlier.
Many planetary imagers want to image using UV or IR frequencies but it's possible only with cameras which have AR coating only.

[ordnance11]

I’m wondering what mount you have? The Celestron mounts mostly have a “solar system align” routine- get a planet in the eyepiece and just align. No need for two or more targets. This will generally give good enough tracking for planetary imaging.

Regards

Mark

Advanced VX EQA mount. It's faster for me to polar align. I could get to align on Venus in the twilight, that is if I can set up early enough. I might just get a solar filter and align on the Sun. And again, location. Good imaging conditions in a city are not going to happen that often and consistently. You're in a "heat island" for one thing. All that concrete, stone, and asphalt is going to radiate heat. The software might be able to get images from the shimmering, but I'd rather remove that from the list of hindrances.

Edited by ordnance11, 12 November 2024 - 08:42 AM.

[lajoswinkler]

No, see the link I posted earlier.
Many planetary imagers want to image using UV or IR frequencies but it's possible only with cameras which have AR coating only.

Protective windows on cameras are normally borosilicate glass with antireflective coating. They will absorb significant IR and UV radiation, making it a somewhat crude UV/IR cut filter. Color cameras already suck at capturing infrared so the protective window should be pretty substantial protection against infrared ghosting.

You can't have coating only, unless the window is made of quartz, and I'm pretty sure ZWO doesn't make those things.

[bunyon]

Advanced VX EQA mount. It's faster for me to polar align. I could get to align on Venus in the twilight, that is if I can set up early enough. I might just get a solar filter and align on the Sun. And again, location. Good imaging conditions in a city are not going to happen that often and consistently. You're in a "heat island" for one thing. All that concrete, stone, and asphalt is going to radiate heat. The software might be able to get images from the shimmering, but I'd rather remove that from the list of hindrances.

 

Yeah, heat island effects are real. I can map my seeing with my neighbors' houses.

 

With the AVX, set the mount down, aim roughly north (that is, rough polar alignment), point at the planet and turn tracking on. That's all you need. There is no need for goto or <2 arc minute PA.

[ordnance11]

Okay, I think I got everything:

 

Can't wait to try it out. I decided to just assemble everything and place it in a padded case. I'm debating if a flip mirror is desirable or just swap out the camera with an eyepiece. when sighting.

[dcaponeii]

Okay, I think I got everything:

 

Can't wait to try it out. I decided to just assemble everything and place it in a padded case. I'm debating if a flip mirror is desirable or just swap out the camera with an eyepiece. when sighting.

You should be collimating using Metaguide (or star imaging at focus) with the optics installed that are planned for imaging when you're doing planetary.  Swapping out camera is not really an option if you're expecting excellent results.  Did you read the FAQ that Andrew wrote?

 

Get a half decent finder and put to the planet on the chip that way.  I can't recommend the flip mirror either I'm afraid as it's just extra spacing with no value added.