Reducers for esprit range of telescope - Forums

Topic starter

Jan 25, 2021

I'm a new user of the starizona apex reducer 0.65x.
Thus is advertised as a reducer/flattener I believe.
Although I am still trying to tune delicately with shim spacers etc and have recently got reasonable results with it like with

Rosette nebula
Here the rosette nebula with modest amounts of data.
I still wouldn't say it is doing a great job of flat fielding.
My esprit 120 native with no flattener gets better flat native results but of course at f7.
With flats taken I am able to process an image like the above rosette but I do think
"are these companies allowed to call their reducer a flattener when it doesn't"? Especially when I believe starizona say its a design built for the esprit range?? 🤔

From other users I have witnessed in vlogs and online forums, say they haven't managed ideal flat fielding..

Please all chip in and share your experiences with reducers and apex reducers for the esprits!!

Engaging

rhedden

Jan 25, 2021

My results with the Esprit 100 + Apex 0.65x reducer have been similar to yours, and I have only a 16 mm sensor diagonal on my camera. I didn't get perfect stars in the corners so far. However, many excellent images on Astrobin taken with highly regarded equipment don't actually have perfect stars in the corners if you look a little more closely. I see that your image still got a Top Pick nomination, so somebody liked it a lot.

I have enjoyed using the reducer the past few months, and I have mostly imaged targets that can withstand a little bit of cropping around the edges. I am actually a little more bothered by my lack of ability to get good flats when the reducer is in place; I always have to flatten the background again during processing. The field of view is still much larger than it would be without the reducer, and I get 2.5x as many subs for the same integration time, so I am happy with it overall. When traveling to a dark site, the extra subs really help.

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Daniel DeSclafani

Jan 26, 2021

I think your image looks great! keep playing around with the backfocus and try your best to get it close. If this is the best that you can get then no worries because it looks great!

Waynescave

Topic starter

Jan 27, 2021

Thankyou for your informative reply. And for letting me know someone nominated as top pick! I didn't know.

You spoke about not getting your image flat even when using flats and this was instant de ja vu to me!

If you're using a cmos camera. Take long flats and flat darks (with matching exposure times obviously)
As 1 Second or less isn't good enough as the electronic signature were trying to get an average of changes radically with each exposure.
Longer 3 second + exposures gives a more accurate measure.
This way your calibrated master flat will correct your integrated image MUCH better!
I recently did this to find a VAST improved calibrated integration!

I discussed on my vlog YouTube channel "Wayne's cave" thus very subject and my findings/results if you may find useful.

Unless of course this is old news to your ears and ignore my every word! 😂

All the best
Wayne

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rhedden

Jan 27, 2021

Yes, the little gold arrow on your image means it was nominated as Top Pick.

I am actually using a CCD camera, and I get good flats with my C11 Edge and with the Esprit at f/5. With the Apex reducer, I get dark corners in my images, as well as a slightly darker, horizontal bar across the top edge of the sensor, which covers about 15% of the sensor on one side only. I really can't explain the horizontal bar! I can process out these aberrations, but it would be better if I did not need to.

I will experiment with the length of my flats. It might just work, so thanks for the tip!

Well Written Concise

Waynescave

Topic starter

Jan 28, 2021

Yes, the little gold arrow on your image means it was nominated as Top Pick.

I am actually using a CCD camera, and I get good flats with my C11 Edge and with the Esprit at f/5. With the Apex reducer, I get dark corners in my images, as well as a slightly darker, horizontal bar across the top edge of the sensor, which covers about 15% of the sensor on one side only. I really can't explain the horizontal bar! I can process out these aberrations, but it would be better if I did not need to.

I will experiment with the length of my flats. It might just work, so thanks for the tip!

I believe the horizontal bar your getting may be the overscan area of the sensor?
Alot of acquisition software gives you the option to not include this area in your subs..

I get the dark corners too with the reducer and hoping that this will lessen as I tune the back focus some more 🤞

AnaTa

Oct 13, 2024

The same here. Apex and no reducer producer the same results as soon as sensor is not big, such as QHY533M. For larger sensors, such as QHY 268M, no reducer produces slightly better results. However, it is easily fixed by Blur-XT in PixInsight.
Clear Skies!

Armen

Jan Erik Vallestad

Oct 13, 2024

Speaking to Starizona they quite firmly believe most star shape issues are related to not getting backfocus properly adjusted.

Stjepan Prugovečki

Oct 13, 2024 · Edited: Oct 13, 2024

AnaTa:
The same here. Apex and no reducer producer the same results as soon as sensor is not big, such as QHY533M. For larger sensors, such as QHY 268M, no reducer produces slightly better results. However, it is easily fixed by Blur-XT in PixInsight.
Clear Skies!

Armen

Hi, that is a bit of strong statement that no reducer produces slightly better results than shown on mentioned Rosette. I have QHY268M on Esprit 120 . Tried 3 reducers and they all produce much better results. They are not 0.63 though. All 3 (Riccardi 0.75, TS 0.79 and Skywatcher 0.77 special one made for E120 ) . All 3 do have reasonably flat field, round stars at corners . If I have to rank them than it will be: Riccardi is the best, TS and Skywatcher are comparable.

Helpful Concise

AnaTa

Oct 13, 2024

Stjepan Prugovečki:
AnaTa:
The same here. Apex and no reducer producer the same results as soon as sensor is not big, such as QHY533M. For larger sensors, such as QHY 268M, no reducer produces slightly better results. However, it is easily fixed by Blur-XT in PixInsight.
Clear Skies!

Armen

Hi, that is a bit of strong statement that no reducer produces slightly better results than shown on mentioned Rosette. I have QHY268M on Esprit 120 . Tried 3 reducers and they all produce much better results. They are not 0.63 though. All 3 (Riccardi 0.75, TS 0.79 and Skywatcher 0.77 special one made for E120 ) . All 3 do have reasonably flat field, round stars at corners . If I have to rank them than it will be: Riccardi is the best, TS and Skywatcher are comparable.

What do you mean “much better results “? Second, you need to read what I wrote. It was about distortion of stars in corners, not SNR. Third, you use different reducer and comparing apples to oranges. All-in-all, I don’t understand what you are arguing about.

Stjepan Prugovečki

Oct 13, 2024

AnaTa:
Stjepan Prugovečki:
AnaTa:
The same here. Apex and no reducer producer the same results as soon as sensor is not big, such as QHY533M. For larger sensors, such as QHY 268M, no reducer produces slightly better results. However, it is easily fixed by Blur-XT in PixInsight.
Clear Skies!

Armen

Hi, that is a bit of strong statement that no reducer produces slightly better results than shown on mentioned Rosette. I have QHY268M on Esprit 120 . Tried 3 reducers and they all produce much better results. They are not 0.63 though. All 3 (Riccardi 0.75, TS 0.79 and Skywatcher 0.77 special one made for E120 ) . All 3 do have reasonably flat field, round stars at corners . If I have to rank them than it will be: Riccardi is the best, TS and Skywatcher are comparable.

What do you mean “much better results “? Second, you need to read what I wrote. It was about distortion of stars in corners, not SNR. Third, you use different reducer and comparing apples to oranges. All-in-all, I don’t understand what you are arguing about.

My apology , I interpreted your statement "no reducer producese slightly better......" wrongly. I interpreded it as "there is no reducer that will produce even slightly better stars" , insead that it is slightly better with no reducer at all. (blame the fact I am not native speaker) That is why I said that all 3 that I used produce close to perfect stars across the APS-C size field . I did not refer to SNR though, just mentioned flat field and round stars.

AnaTa

Oct 13, 2024

Stjepan Prugovečki:
AnaTa:
Stjepan Prugovečki:
AnaTa:
The same here. Apex and no reducer producer the same results as soon as sensor is not big, such as QHY533M. For larger sensors, such as QHY 268M, no reducer produces slightly better results. However, it is easily fixed by Blur-XT in PixInsight.
Clear Skies!

Armen

Hi, that is a bit of strong statement that no reducer produces slightly better results than shown on mentioned Rosette. I have QHY268M on Esprit 120 . Tried 3 reducers and they all produce much better results. They are not 0.63 though. All 3 (Riccardi 0.75, TS 0.79 and Skywatcher 0.77 special one made for E120 ) . All 3 do have reasonably flat field, round stars at corners . If I have to rank them than it will be: Riccardi is the best, TS and Skywatcher are comparable.

What do you mean “much better results “? Second, you need to read what I wrote. It was about distortion of stars in corners, not SNR. Third, you use different reducer and comparing apples to oranges. All-in-all, I don’t understand what you are arguing about.

My apology , I interpreted your statement "no reducer producese slightly better......" wrongly. I interpreded it as "there is no reducer that will produce even slightly better stars" , insead that it is slightly better with no reducer at all. (blame the fact I am not native speaker) That is why I said that all 3 that I used produce close to perfect stars across the APS-C size field . I did not refer to SNR though, just mentioned flat field and round stars.

Reducer mentioned there was Apex. It produces some elongation. But it is not big deal, easily fixed.
Clear Skies!