1st ASK3 Image from S'pore (New image added From Good Fri)
- yltansg
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1st ASK3 Image from S'pore (New image added From Good Fri)
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.
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.
Last edited by yltansg on Thu Mar 31, 2016 5:40 am, edited 6 times in total.
- pedro
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Re: First ASK3 Image from Singapore + close-to-real HA color
Nice images. Can you tell us more regarding the ASK 3
I would like to receive more info
thanks
I would like to receive more info
thanks
Pedro Re'
https://pedroreastrophotography.com/
https://pedroreastrophotography.com/
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Re: First ASK3 Image from Singapore + close-to-real HA color
Great images Alfred! That looks a great mod, yes, more details please
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Re: First ASK3 Image from Singapore + close-to-real HA color
Super set of images
.
.
.
Mike Garbett
Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
.
.
Mike Garbett
Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
Re: First ASK3 Image from Singapore + close-to-real HA color
Nice results here! Nice custom set up as well! Cheers
Tyson- my amateur photography https://www.flickr.com/photos/134930728@N02/
Lunt LS50THa
Meade 10" F10 ACF
Skywatcher AZ-EQ6 GT
ASI224MC
Orion Skyview Pro
Lunt LS50THa
Meade 10" F10 ACF
Skywatcher AZ-EQ6 GT
ASI224MC
Orion Skyview Pro
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Re: First ASK3 Image from Singapore + close-to-real HA color
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
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
Last edited by Valery on Sun Mar 27, 2016 3:16 pm, edited 2 times in total.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
- yltansg
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Re: First ASK3 Image from Singapore + close-to-real HA color
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
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
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
Interesting! Valery, can you describe what all the different bits do!
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
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.
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.
- yltansg
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
Tcb37 wrote: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
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
Thanks Alfred good luck with the doublestack
- yltansg
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
Thanks Derek. The sky is completed covered with clouds since Good Friday. Looks like I have to wait for next weekend
Re: First ASK3 Image from Singapore + close-to-real HA color
Hi Alfred,yltansg wrote:
For now I am using a Baader ERF. Still looking for a vendor to fabricate a cell for Valery's D-ERF
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
Aleksey
-------------
Lunt LS100THa, Coronado SolarMax II 90 Filter + BF 15 on WO Megrez 90, PST + SW 1025 mod, Quark + SW150/750 in test mode
-------------
Lunt LS100THa, Coronado SolarMax II 90 Filter + BF 15 on WO Megrez 90, PST + SW 1025 mod, Quark + SW150/750 in test mode
- yltansg
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Re: First ASK3 Image from Singapore + close-to-real HA color
Dear Aleksey,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
Thanks very much for sharing the cell design.
Alfred
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
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:
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:
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
These are beautiful! Happy Easter!
Alexandra
Alexandra
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Nice work Alfred...sharp set of images!!!
Brian
Brian
Brian Colville
Maple Ridge Observatory
Cambray, ON Canada
Photos: https://www.flickr.com/photos/185395281@N08/albums
10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM Pro+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI462MM
2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL, G-Band & CaK Setup: Lunt Wedge & Lunt B1800CaK, Baader K-Line and Altair 2nm G-Band filter
ASI1600MM, ASI432MM, ASI294MM Pro, ASI174MM, ASI462MM
Maple Ridge Observatory
Cambray, ON Canada
Photos: https://www.flickr.com/photos/185395281@N08/albums
10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM Pro+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI462MM
2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL, G-Band & CaK Setup: Lunt Wedge & Lunt B1800CaK, Baader K-Line and Altair 2nm G-Band filter
ASI1600MM, ASI432MM, ASI294MM Pro, ASI174MM, ASI462MM
- yltansg
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
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
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
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Great additions there Alfred!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: 1st ASK3 Image from Singapore + close-to-actual HA color
This is not true, Alfred. What you really did with ARIES components? I believe you did nothing with them.yltansg wrote:Thanks Alexandra. Lots of work needed to bring out its best performance.
All problems were as you have finally realized in a LS50THa which were not up to necessary level.
Finally you found a good sample which has a good performance.
The second your problem was that you have the difficulty to attach a camera and a barlow lens to the LS50THa telescope.
And these difficulties can be described as needed a lot of work. If only your LS50THa will be OK from the first time and
if you have right camera and barlow you'd nothing to do to make it work - it will work right out of the box, plug and play.
Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
- yltansg
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Thanks Mark for your kind comments.
Valery is right, I did not have to do any work on ASK 3 components. Valery provided simple instructions and ASK 3 was easy to assemble.
All the work was done on getting the right equipment and getting them to work well. On top of my Lunt LS50THA, I had to borrow 2 more LS50THA to find the one that is good. Have to thank my friends for lending their equipment and Valery for pointing out what to look for, etc. Before this, I had to source for 2 small signature adapters to use with the BF1200 to achieve focus with cameras. I tried 3 different types of barlows without success and tried to buy the barlows that Valery used. I wrote to WO and NPZ to buy barlows but without success. Then I tried 4 different types of cameras before settling on PG Grasshopper 3. Many of these work are necessary because I am using ASK 3 for the first time. I believe that it will get better as I get more familiar with the equipment.
Right now I am still getting uneven image and inconsistent contrast. This is the first time I am using a LS50THA and I believe getting good contrast and even image will come by with more practice, hopefully it is not an equipment problem. Every bit of work is worth it because I am improving
Here is one more image from yesterday. This time I used another camera - Grasshopper 50S5M.
This is a cropped image to remove the parts that have uneven contrast.
I am still not quite happy with it because I believe the contrast and focus can be better. I also have a long way to improve my post processing workflow.
By the way, my ASK is Version 3, an improvement over the previous version. I am glad to get V3 because I thought I was getting V2 or V2.5 when I made a commitment to buy.
Thanks Valery for a fine piece of optics and the good instructions certainly help.
Alfred
Valery is right, I did not have to do any work on ASK 3 components. Valery provided simple instructions and ASK 3 was easy to assemble.
All the work was done on getting the right equipment and getting them to work well. On top of my Lunt LS50THA, I had to borrow 2 more LS50THA to find the one that is good. Have to thank my friends for lending their equipment and Valery for pointing out what to look for, etc. Before this, I had to source for 2 small signature adapters to use with the BF1200 to achieve focus with cameras. I tried 3 different types of barlows without success and tried to buy the barlows that Valery used. I wrote to WO and NPZ to buy barlows but without success. Then I tried 4 different types of cameras before settling on PG Grasshopper 3. Many of these work are necessary because I am using ASK 3 for the first time. I believe that it will get better as I get more familiar with the equipment.
Right now I am still getting uneven image and inconsistent contrast. This is the first time I am using a LS50THA and I believe getting good contrast and even image will come by with more practice, hopefully it is not an equipment problem. Every bit of work is worth it because I am improving
Here is one more image from yesterday. This time I used another camera - Grasshopper 50S5M.
This is a cropped image to remove the parts that have uneven contrast.
I am still not quite happy with it because I believe the contrast and focus can be better. I also have a long way to improve my post processing workflow.
By the way, my ASK is Version 3, an improvement over the previous version. I am glad to get V3 because I thought I was getting V2 or V2.5 when I made a commitment to buy.
Thanks Valery for a fine piece of optics and the good instructions certainly help.
Alfred
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Alfred:
Super instrument and mod. The result are super images.
Well done,
Eric.
Super instrument and mod. The result are super images.
Well done,
Eric.
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Hi Eric and Derek,
Thanks for your kind comments. There are still many areas of improvement to work on, especially on my skills.
Alfred
Thanks for your kind comments. There are still many areas of improvement to work on, especially on my skills.
Alfred
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Alfred,
The unevenness is the immanent sign of a small sub aperture etalon. The larger the ratio
Dobj / Det the smaller sweet spot will be seen.
The best is an objective (front mounted) etalon. If the etalonis smaller than objective and it is
internally mounted (with increased field angle) then a sweet spot will starts to shrink.
In the ideally made telescope with etalon size equal to 1/2 of an feeding aperture size and about 0,7A
bandwide, the sweet spot will be of 1/2 degree in diameter = about the sun diameter.
In such a telescope we can see a full sun disk in H-a with maximal contrast at the center and somewhat
lesser contrast at the limb where the bandpass of the etalon shifts towards blue (starts to leave the H-a
from the blue wing) and transmit less H-a and more continuum light.
Your etalon size is 1/7,5 of the feeding aperture size. So, it the case of 0,7A bandpass the sweet spot
diameter will be about 1/4 of the sun disk. Judging the H-a structures on your pictures I can estimate
your LS50THa etalon as about 0,5A or even slightly narrower (which is very nice ended). Therefore
the sweet spot in this your setup is even smaller than 1/4 sun disk circle. May be 1/5 or less.
What you can adjust is make it maximally symmetrical in the FOV.
Then you can work in such ways:
1. Use a barlow lens in a front of your blocking filter. This will increase liner size of the sweet spot and
can fully cover your camera chip (if the chip use is not too large).
In this case (slower F/D at the entrance of the BF) the blocking filter will work even better and better blocks
continuum light. The drawback is exposure time increasing.
2. Use smaller chip
3. Use a ROI with rectangle inscribed in a sweet spot circle.
No other optimizing is possible in this system. The small size of the sweet spot is its principal limitation and
this is the payment for it's lower cost.
IMPORTANT: the ASK-3 consists also all the components of the ASK-1 and ASK-2. So, you can use your
150mm telescope in a several combinations:
1. ASK-1 when a LS50FHa used as an etalon + refocusing objective + focuser + BF + camera.
If a LS50FHa is good and not require the tilt to get in a CWL of H-a, then you will have full disk in H-a
like you have it in a LS50THa itself.
2. ASK-2 - you can use two LS50FHa and have a DS.
3. You can place a good LS50FHa between the first component of the ASK and your present LS50THa and get
a DS system.
I believe that with a time and more experience you will give this kit a full use in different combinations.
Good luck.
Valery
The unevenness is the immanent sign of a small sub aperture etalon. The larger the ratio
Dobj / Det the smaller sweet spot will be seen.
The best is an objective (front mounted) etalon. If the etalonis smaller than objective and it is
internally mounted (with increased field angle) then a sweet spot will starts to shrink.
In the ideally made telescope with etalon size equal to 1/2 of an feeding aperture size and about 0,7A
bandwide, the sweet spot will be of 1/2 degree in diameter = about the sun diameter.
In such a telescope we can see a full sun disk in H-a with maximal contrast at the center and somewhat
lesser contrast at the limb where the bandpass of the etalon shifts towards blue (starts to leave the H-a
from the blue wing) and transmit less H-a and more continuum light.
Your etalon size is 1/7,5 of the feeding aperture size. So, it the case of 0,7A bandpass the sweet spot
diameter will be about 1/4 of the sun disk. Judging the H-a structures on your pictures I can estimate
your LS50THa etalon as about 0,5A or even slightly narrower (which is very nice ended). Therefore
the sweet spot in this your setup is even smaller than 1/4 sun disk circle. May be 1/5 or less.
What you can adjust is make it maximally symmetrical in the FOV.
Then you can work in such ways:
1. Use a barlow lens in a front of your blocking filter. This will increase liner size of the sweet spot and
can fully cover your camera chip (if the chip use is not too large).
In this case (slower F/D at the entrance of the BF) the blocking filter will work even better and better blocks
continuum light. The drawback is exposure time increasing.
2. Use smaller chip
3. Use a ROI with rectangle inscribed in a sweet spot circle.
No other optimizing is possible in this system. The small size of the sweet spot is its principal limitation and
this is the payment for it's lower cost.
IMPORTANT: the ASK-3 consists also all the components of the ASK-1 and ASK-2. So, you can use your
150mm telescope in a several combinations:
1. ASK-1 when a LS50FHa used as an etalon + refocusing objective + focuser + BF + camera.
If a LS50FHa is good and not require the tilt to get in a CWL of H-a, then you will have full disk in H-a
like you have it in a LS50THa itself.
2. ASK-2 - you can use two LS50FHa and have a DS.
3. You can place a good LS50FHa between the first component of the ASK and your present LS50THa and get
a DS system.
I believe that with a time and more experience you will give this kit a full use in different combinations.
Good luck.
Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
- yltansg
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Re: 1st ASK3 Image from S'pore (New images added on Easter)
Valery,
With your explanation, I now understand what I have experienced. I will try to put a barlow in front of the blocking filter this weekend and also the double-stacked configuration. Thanks for your help.
I didn't realise the ASK3 is so versatile. Great job on the design.
Alfred
With your explanation, I now understand what I have experienced. I will try to put a barlow in front of the blocking filter this weekend and also the double-stacked configuration. Thanks for your help.
I didn't realise the ASK3 is so versatile. Great job on the design.
Alfred
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Re: 1st ASK3 Image from S'pore (New images added From Good F
Here is another image from my first light of this hybrid scope on Good Friday. Are those bubbles?
- marktownley
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Re: 1st ASK3 Image from S'pore (New image added From Good Fr
Nice addition Alfred!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!