1st ASK3 Image from S'pore (New image added From Good Fri)

[yltansg]

A blessed Good Friday greeting from Singapore to all!

The sky condition was not good, lots of clouds and it was very turbulent, boiling in fact.

The setup - Celestron 150 XLT Omni refractor + ASK 3 + Lunt LS50THA with x2.5 barlow and Grasshopper 2.8Mp camera.



This is the outcome -


There is still lots of room for improvement. I need to work on (1) post-processing, (2) get spot-on focus and (3) tune the LS50THA for uniform image and good contrast. Overall I am very pleased with ASK3. Good job Valery!

Here is the PNG file of the cropped 100frame-stacked image.
https://drive.google.com/open?id=0B1xv2 ... nVfREd0N3M Unprocessed PNG

Would appreciate it if you can help to show me a better post processed image of it. Thanks in advance


Other images taken on the same day:


ASI 174MM on a Borg 76 with SF50DS


ASI 185MC on a Borg 76 with SF50DS. I don't normally image with colour cameras. Imaging with ASI 185MC was to try to replicate the H-Alpha colour we see visually through the EP.

[xn44]

good images!

[pedro]

Nice images. Can you tell us more regarding the ASK 3

I would like to receive more info

thanks

[marktownley]

Great images Alfred! That looks a great mod, yes, more details please

[grimble_cornet]

Super set of images

[T McVicar]

Nice results here! Nice custom set up as well! Cheers

[Derek Klepp]

Alfred a good result.

[Valery]

Hi Alfred,

My congratulations that you finally found a good Lunt 50THa for your nice setup. This one is definitely a keeper and
can work not only in the ASK, but also as full disk imager.

As soon as you will add LS50F etalon (between the ASK front component and the LS50T telescope) you will get
absolutely fantastic DS imaging setup.

Good luck with this new setup and it's further development into a DS.


As for the processing:

1. Better to record longer movies at maximal possible speed. With duration 40-50 sec.

2. Use the Autostekkert AS2! for frames selection and stacking. Place reference points density at 25 (good seeing) or 40 at poor seeing.

3. Use 600, 400 and 300 frames to stack out of at least 1500 or even more.

4. Process the raw stacked images in the AstraImage 3.0 and then in a PhotoShop.

For imaging:

1. Use even a bit larger scale

2. Use lowest gamma settings (for surface details)

3. Perform focusing at 2x larger scale ( this is FireCapture function).


Valery

[yltansg]

Thanks everyone for your kind comments. I have to put in more work to do justice to ASK3.

Thanks Valery for the tips.

The ASK3 kit is from Valery. He would be the best person to provide detailed description. I will show pictures of the different components.

The scope assembled:


For now I am using a Baader ERF. Still looking for a vendor to fabricate a cell for Valery's D-ERF


A closer look at the collimating lens and interface to the LS50THA

[marktownley]

Interesting! Valery, can you describe what all the different bits do!

[Derek Klepp]

Thanks for the set up pics Alfred .

[Montana]

Wow! beautiful images

Alexandra

[yltansg]

Thanks Alexandra. Lots of work needed to bring out its best performance.

My setup consists of a Celestron 150mm F/5 Omni XLT telescope fitted with ASK3 kit, a Lunt LS50TH telescope and Point Gray Research (PGR) Grasshopper 3 (Sony ICX674 chip). It can be transformed to a double-stacked imaging configuration by adding a second H-Alpha etalon in front of the Lunt LS50THA telescope. From my interaction with Valery and literature available on solarchat, this is my understanding of the ASK3 that i have:

The ASK, with a designed Strehl ratio of higher than 0.97 across entire 1 degree field (in H-Alpha wavelength), consists of two parts:

a. A 60mm cemented triplet collimator lens which transforms the F/5 cone beam from the 150mm refractor into a parallel collimated beam of about 50mm diameter. The collimator lens also provides correction for spherical abberation (at H-Alpha wavelength), coma and astigmatism. This collimated 50mm diameter beam will enable the Lunt LS50THA to operate at its best efficiency.

b. A 60mm doublet objective lens which refocuses the parallel beam and passed it to the etalon(s). The objective lens, acting with the triplet collimator produces a flat unabberated image of 1 degree diameter.

Focussing is done using the helical focuser on the LS50THA which can be a challenge. I believe the greatest challenge is to tinker the double-stacked etalons to achieve the orientation of the etalons and blocking filter for best image.

Cheers.

[Tcb37]

Interesting. Is the Ls50 not modded and just attaches to the XLT?

[yltansg]

Interesting. Is the Ls50 not modded and just attaches to the XLT?

Hi Tcb37,

The LS50 is attached to the XLT. No mod required.

Alfred

[Tcb37]

Awesome! I'll have to ask Valery about it.
Thanks!

[Derek Klepp]

Thanks Alfred good luck with the doublestack

[yltansg]

Thanks Derek. The sky is completed covered with clouds since Good Friday. Looks like I have to wait for next weekend

[Rybak]

For now I am using a Baader ERF. Still looking for a vendor to fabricate a cell for Valery's D-ERF

Hi Alfred,
Here is the cell of my design for Valery's 165mm D-ERF. I use in on SW 150/750. Any mechanic can do it.

http://solarchat.natca.net/viewtopic.ph ... 87#p181087

[yltansg]

Hi Alfred,
Here is the cell of my design for Valery's 165mm D-ERF. I use in on SW 150/750. Any mechanic can do it.

http://solarchat.natca.net/viewtopic.ph ... 87#p181087

Dear Aleksey,

Thanks very much for sharing the cell design.

Alfred

[yltansg]

The skies opened up on Easter Day for an hour. Unfortunately the very turbulent condition (boiling) caused it almost impossible to get focus. The setup is similar to the one used for the first image taken on 25 Mar 16. Here are some images taken on Easter.

I was glad to have a more uniform image, 130 frames from 3,000 frame recording:


Cropped image to take out the uneven portion:


Could only use 78 frames from a 3,000 frame recording for this image:

[Montana]

These are beautiful! Happy Easter!

Alexandra

[MapleRidge]

Nice work Alfred...sharp set of images!!!

Brian

[yltansg]

Thanks Brian and Alexandra for your kind comments.

I have found a machinist to fabricate a cell to hold Valery's D-ERF. Hope to compare the performance of Baader 160mm D-ERF with that of ARIES 165mm D-ERF soon using the same Celestron 150 XLT R + LUNT 50 THA setup.

Alfred

[marktownley]

Great additions there Alfred!