Celestron C8 F10 + PST CaK + SAFIX test

[Valery]

Hi all,

During last decade of June I have tested our ARIES 214mm and 265mm 3-bands D-ERF (with C8 and C11 scopes respectively) in
the Ca K line. For isolation of the Ca K line I have used PST Ca K filter. For compensation of a heavy spherical aberration at 393nm
the ARIES SAFIX device has been used. This is a variable spherical aberration corrector. UV grade.

I also imaged the sun with a 393nm Edmund pre-filter with 10nm bandwidth. The SAFIX has been used here too.

Here are images taken with my 203mm Celestron C8 telescope and PGR Flea3 ICX445 chip camera.

One can see that images are sharp enough for such an UV range and average seeing condition (4-6 out of 10). SAFIX does it work just fine in nullyfying of a heavy SA at 393nm.


Thanks for looking.


Valery

[Derek Klepp]

Very impressive Valery thanks for the pictures.

[krakatoa1883]

This setup seems to work fine, indeed, images are very detailed. Is SAFIX a commercial device or is it produced on order ? How do you set the grade of correction required ?

[Merlin66]

Valery,
Could you take a similar series of images without the SAFIX for comparison purposes?
(The reason I ask is that we regularly image the spectrum down around the 3900A with a bandwidth of <0.05A and would like to know if your corrector could/ would improve the results)

[eroel]

Valery:
Really nice clean and crisp work, I still have the SAFIX and have used it to correct the SA of some refractors and also SCT.
I would like to know where do you put the SAFIX in respect to the optical/filters and camera side.
I have not been able to keep testing the Aries D-ERF with my TEC 10" Mak, due to the raining season, at the rural observatory it rains a lot and I just go on weekends.
Hope that soon the raining season will start diminishing.
Best regards,
Eric.

[marktownley]

That works well in that setup Valery!

[Valery]

This setup seems to work fine, indeed, images are very detailed. Is SAFIX a commercial device or is it produced on order ? How do you set the grade of correction required ?

SAFIX has been made in a very limited series - 50 samples.

I have two samples and can part with one only.

Correction can be done easily looking at the screen. Rotate the barrel clock and counterclock wise and you see how sharp
the image is on the screen.

Valery

[Montana]

Super granulation Valery in the CaK, very nice indeed

Alexandra

[Wah]

Super detail! Is there any ERF for CaK being used?
Where can I buy SAFIX? Thanks!

[p_zetner]

Beautiful demonstration, Valery.

The granulation in the 393nm continuum is amazing. It must be much harder to image than the usual ~550nm.
I have a question about your Edmund Optics filter. My understanding was that these filters, generally, have significantly worse than lambda/4 (at 633nm) wavefront distortion. Your placement of the filter must minimize this problem. Where do you put it in your Optics train, near the camera?

Cheers.
Peter.

[Valery]

Beautiful demonstration, Valery.

The granulation in the 393nm continuum is amazing. It must be much harder to image than the usual ~550nm.
I have a question about your Edmund Optics filter. My understanding was that these filters, generally, have significantly worse than lambda/4 (at 633nm) wavefront distortion. Your placement of the filter must minimize this problem. Where do you put it in your Optics train, near the camera?

Cheers.
Peter.

Peter,

Imaging at 393nm is not MUCH harder. Just harder, sometime really harder, but not much. At least if your aperture is not 14" and if your telescope is well corrected at 393nm.

My Edmund filter specified to be at least 1/4 wave surface error = 1/8 wave in transmittance. It is about in 100mm prior to focus and works as residual pre-filter. It can be mounted also near the camera - if it's accuracy is not sufficient.

[Valery]

Super detail! Is there any ERF for CaK being used?
Where can I buy SAFIX? Thanks!

The 3-band D-ERF filter has been used. It transmits 393nm and 396nm for Ca II K and H, 430nm for G-band and 656nm for H-a.

You can buy it from me (I have only one UV grade sample for sale) or try to fishing it at the AstroMart.


Valery

[Valery]

Valery:
Really nice clean and crisp work, I still have the SAFIX and have used it to correct the SA of some refractors and also SCT.
I would like to know where do you put the SAFIX in respect to the optical/filters and camera side.
I have not been able to keep testing the Aries D-ERF with my TEC 10" Mak, due to the raining season, at the rural observatory it rains a lot and I just go on weekends.
Hope that soon the raining season will start diminishing.
Best regards,
Eric.

Hello Eric,

You don't need the SAFIX if you will image the Sun at CaK/H with your 10" Mak. SAFIX is required for using in SCT and fast refractors.


Valery

[eroel]

Valery:
Thanks for the information, I was thinking on my 102mm f/9 Meade refractor where I have my PST CaK mod unit.
I have used the SAFIX unit with this refractor to image the moon and it did really helped getting a better image.
Best regards,
Eric.

[Valery]

Valery,
Could you take a similar series of images without the SAFIX for comparison purposes?
(The reason I ask is that we regularly image the spectrum down around the 3900A with a bandwidth of <0.05A and would like to know if your corrector could/ would improve the results)

I believe that SAFIX will not help because of it's limited FOV. This device is for a high resolution work.
May be a specially designed and custom made corrective optics will be a better option?

However, tell me what is the feeding objective in your system.


BTW. Is this possible to image at 8542,1A wave length? I saw a few professional shots at this wave length and they are the mot impressive sun images taken from the earth ground. Spectacular mixture of Ca II and H-a - like structures of middle and upper chromosphere. And that images were taken with large spectrogeliograph with about 0,1A bandwidth.

Valery.

[Valery]

Valery:
Thanks for the information, I was thinking on my 102mm f/9 Meade refractor where I have my PST CaK mod unit.
I have used the SAFIX unit with this refractor to image the moon and it did really helped getting a better image.
Best regards,
Eric.

If the seeing (early morning at summer time and during first part of the day at winter) will be OK, you will easy
image the sun at Ca II K with your 10" Mak and small 4" refractor can't compete vs 10" monster.