Testing a simple AR 152

[astroavani]

January, 22-2019; 03:43 a.m. 03:54 p.m.
Mosaic from 15 films with telescope AR 152mm Explore Scientific. Each film with 1200 frames of which were stacked the best 150.
Explore Scientific AR 152 + ASI 290 MC + Solar Continuum + UV-IR cut.
https://www.astrobin.com/full/387399/0/

[jetstream]

Very sharp image Avani!

Do you have examples using differing apertures such as a C8? I'm thinking of a lunar imaging telescope and would like to see the levels of fine detail increasing apertures bring in imaging. I'd like a C14 but....

Also what mount do you use? I have an AZ EQ6 that I use for visual which I hope to use for imaging the moon.

[astroavani]

No one is interested in knowing why the use of these filters listed?

[jetstream]

Oh yes lol!

Guessing: to clear up any scope false color using the green Continuum and then the UV/IR cut to reduce any distracting colors to the camera sensor?

I probably embarrassed myself with this answer ? but I really would like to know. The jet black background immediately caught my eye Avani.

[Stu]

17 hours ago, jetstream said:

imaging

   

 

 

[jetstream]

lol!

Stu, I sure wish I had a well collimated Intes ?

I love observing lunar and hope to image it in the near future. I'm not sure about the aperture though- a C14 would be great but a bit too expensive for me. Avani gives us so much information, many kudos!

[astroavani]

1 hour ago, jetstream said:

Oh yes lol!

Guessing: to clear up any scope false color using the green Continuum and then the UV/IR cut to reduce any distracting colors to the camera sensor?

I probably embarrassed myself with this answer ? but I really would like to know. The jet black background immediately caught my eye Avani.

Yes, you are right friend Gerry!
It should be better explained as follows:

In fact I tested several filters, for example: UV-IR cut alone, Long Pass 610nm, IR Pass 685, Green planetary, Solar Continuum alone and finally the combination Solar Continuum + UV-IR cut.
Of all the possible combinations, 610nm, and the IRs were the ones that showed me the lowest resolution.
Green alone gave a great result, but it was with the combination posted that the resolution was better. This even visually was noticeable on the PC screen.
It can be explained by the fact that long waves have lower resolution than short waves, but it is probably not the only explanation.
If so, the best result would have to be with Blue or even violet which are even shorter waves, but then the seeing would have to be excellent, which was not the case.
By analyzing tests for Achromatic refractors, one notices that they are best corrected always for the color green. Taking this into consideration I deduced that green would be the color that would give me the best result, at the same time I imagined that the narrower the bandwidth this result should be even better, so the use of the Solar Continuum that has a narrow passband exactly in the green. Already the use of the combined UV-IR cut is due to tests I've seen in solar photography (http://www.schursastrophotography.com/solar/Articles/solararticle3.html) where the author mentions that the Solar Continuum has quite a leak pronounced on IR and that it would be advisable to use a UV-IR cut to block this leak.
The result is there! I can say that the seeing was at most 2.5 / 5 but that the little opening of only 152mm also contributed to a satisfactory result.
Any questions, please do not hesitate to contact us!
 

[astroavani]

19 hours ago, jetstream said:

Very sharp image Avani!

Do you have examples using differing apertures such as a C8? I'm thinking of a lunar imaging telescope and would like to see the levels of fine detail increasing apertures bring in imaging. I'd like a C14 but....

Also what mount do you use? I have an AZ EQ6 that I use for visual which I hope to use for imaging the moon.

Hello, Gerry!
I have had many telescopes, almost all for the purpose of lunar and planetary imagery, other than those I have tested from other colleagues.
Just to get an idea: C8, C9,25, C11 and C14, GSO Newton 8 ", 10" and 12 ", Orion UK 10" Newton, Sky Watcher Mak 150mm, Acro 120, 127 and 152mm Refractors, Meade LX200 10 "ACF.
Some take advantage in some things and others in others, but for lunar and planetary photography my favorites are the SCT.
I consider a C8 to be an excellent telescope for this venture (sometimes I regret having sold mine, so much that I'm looking for a C9.25) it combines a good resolution with excellent portability. If you can get one, make sure you will not regret it. Below are some photos and finally a GIF made with a C8 XLT and EQ-5 motorized mount:
https://www.astrobin.com/335264/?nc=astroavani
https://www.astrobin.com/full/300902/B/?nc=astroavani
https://www.astrobin.com/full/240728/0/?nc=astroavani
https://www.astrobin.com/full/237274/0/?nc=astroavani
https://www.astrobin.com/286216/?nc=astroavani

PS: I think that photo of the South Pole should clear all doubts!

[jetstream]

1 hour ago, astroavani said:

It can be explained by the fact that long waves have lower resolution than short waves, but it is probably not the only explanation.
If so, the best result would have to be with Blue or even violet which are even shorter waves, but then the seeing would have to be excellent, which was not the case.

Thanks so much Avani! I am now taking notes.

I did not know about the resolution vs waves and also seeing vs wavelength. So I can see now that in VG seeing that imaging in shorter wavelengths is best and if seeing is not the best go longer in wavelenghts. I see matching wavelenghts to conditions and also the telescope works very well.

This is very valuable information.

I knew from solar observing with my Baader wedge (uses a solar continuum) that it does have an IR leak as the graphs show. I purchased a UV/IR from Beloptik on KG3 for multiple uses visually.

This thread has taught me a lot in a short time, many thanks Avani and yes when I have more questions I will contact you- this is great!

[jetstream]

1 hour ago, astroavani said:

I consider a C8 to be an excellent telescope for this venture

These are superb images, there is no question that a C8 can give me the level of detail I'm looking for. The mountains are so sharp with many fine features showing that I think this scope would be a VG place to begin. And yes, these photos do remove all doubts- excellent images.

Avani, do you consider the C8 "Edge" model to be worth the extra cost ?

[astroavani]

21 minutes ago, jetstream said:

These are superb images, there is no question that a C8 can give me the level of detail I'm looking for. The mountains are so sharp with many fine features showing that I think this scope would be a VG place to begin. And yes, these photos do remove all doubts- excellent images.

Avani, do you consider the C8 "Edge" model to be worth the extra cost ?

Hello Gerry!
My C14 is Edge, in planetary should have no difference in relation to the XLT model. This is because planets occupy only the center of the field where coma does not manifest. We can prove this with the great photos made by Damian and Chris Goo using the traditional model.
Now for lunar I believe that the Edge for being coma free will present a better correction on the edges, we have to consider that the Moon usually occupies the whole field, so the edges will be better corrected.
About whether or not it's worth the investment, just our pocket is what you can say!

[Ruud]

Oh Avani, that looks very, very good!

I love it! Thank you for posting this test.

[jetstream]

11 minutes ago, astroavani said:

Now for lunar I believe that the Edge for being coma free will present a better correction on the edges, we have to consider that the Moon usually occupies the whole field, so the edges will be better corrected.

This makes complete sense Avani and I have one more question ( for now tonight!). I noticed you used an ASI224 with the C8 vs the ASI290MC with the C14- was this just an upgrade or does the 290 match the C14 better. Do these cameras have the same chip size?

I guess I'm asking which camera to match a C8 Edge.

Btw, the C8, which should cool a bit faster than a bigger SCT could take our big temperature swings- from 0c to -30c in the winter.

Edge it is!

[astroavani]

It was only an upgrade, as the ASI290 has smaller pixel presents a better resolution, which for lunar and planetary is desired. I almost did not take photos with ASI 290 + C8 because as soon as I bought the camera I sold the C8. What I noticed was that with the 224 the result is better using a 2X PM, already with the 290 gets better using only the camera.

I usually leave the telescope acclimatizing outside 2 hours before I start imaging!

[jetstream]

Good to know and now I have an idea of the optics/camera portion of lunar imaging. I'm going to keep an eye out for a C8 Edge and also a camera. This summer an observatory is being built up on a section of the property with few local thermals and should work well. I'm excited about all this actually.

It sounds like either camera will work for me.

I have an out building that my scopes can stay cooled which should benefit the SCT as well. Realistically I will try lunar imaging in a few months.

Great information in your thread Avani, from the 152 achro/filters to much more!

 

[Rob]

12 hours ago, astroavani said:

No one is interested in knowing why the use of these filters listed?

Yes please!. I'm wondering if I could use a similar combo in my AR 127L to tame the (limited) CA?.

Rob

[astroavani]

11 hours ago, Rob said:

Yes please!. I'm wondering if I could use a similar combo in my AR 127L to tame the (limited) CA?.

Rob

Certainly expensive yes Rob!
And I already answered the above because, maybe you have passed directly without reading, however I will repeat here:

In fact I tested several filters, for example: UV-IR cut alone, Long Pass 610nm, IR Pass 685, Green planetary, Solar Continuum alone and finally the combination Solar Continuum + UV-IR cut.
Of all the possible combinations, 610nm, and the IRs were the ones that showed me the lowest resolution.
Green alone gave a great result, but it was with the combination posted that the resolution was better. This even visually was noticeable on the PC screen.
It can be explained by the fact that long waves have lower resolution than short waves, but it is probably not the only explanation.
If so, the best result would have to be with Blue or even violet which are even shorter waves, but then the seeing would have to be excellent, which was not the case.
By analyzing tests for Achromatic refractors, one notices that they are best corrected always for the color green. Taking this into consideration I deduced that green would be the color that would give me the best result, at the same time I imagined that the narrower the bandwidth this result should be even better, so the use of the Solar Continuum that has a narrow passband exactly in the green. Already the use of the combined UV-IR cut is due to tests I've seen in solar photography (http://www.schursastrophotography.com/solar/Articles/solararticle3.html) where the author mentions that the Solar Continuum has quite a leak pronounced on IR and that it would be advisable to use a UV-IR cut to block this leak.
The result is there! I can say that the seeing was at most 2.5 / 5 but that the little opening of only 152mm also contributed to a satisfactory result.
Any questions, please do not hesitate to contact us!

A long time ago I had a Explore Scientific AR 127mm and I can tell you that the procedure for achromatic refractors should always be the same. They are always best corrected for the green wavelength, so by logic this would be the band that we should explore more.
Already with SCT I realized that the filter that gave the best results was the IR Pass 685nm of Baader. Going back to the previous logic, I know that the SCT has better perfomance in the red wavelengths, and also in the IR, besides we can not forget that with greater aperture, photos in the IR Pass is a good way to dribble the bad seeig.

 

[astroavani]

17 hours ago, jetstream said:

Good to know and now I have an idea of the optics/camera portion of lunar imaging. I'm going to keep an eye out for a C8 Edge and also a camera. This summer an observatory is being built up on a section of the property with few local thermals and should work well. I'm excited about all this actually.

It sounds like either camera will work for me.

I have an out building that my scopes can stay cooled which should benefit the SCT as well. Realistically I will try lunar imaging in a few months.

Great information in your thread Avani, from the 152 achro/filters to much more!

 

My friend Gerry!
Any of the 3 cameras that you buy will perform well with a C8: ASI 224 + barlow 2X, ASI 290 without barlow or even ASI 174 with a Barlow 2X or 3X will give excellent results.
I personally will get rid of this AR 152 to get a C9.25, in fact I bought it with the intention of making solar, but I already realized that this is not my beach, apart from the fact that, to make high resolution solar, I will still need more accessories that are expensive and difficult to get here in Brazil.
I want a lot in the near future to get an ASI 174 mono, not to make colored photos using filters wheel, but to make polka dots taking advantage of 100% of the pixel in the IR Pass with C9,25 and C14 as well as to image the planets at specific wavelengths such as UV, IR 742, IR 850 and even in Methano.
Note that in a color camera, you never take 100% of the pixels that are working at only a certain wavelength. In the above photo made with that set, I used only 50% of the camera pixel.