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ASKAR FMA180 40mm aperture apochromatic telescope.


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13 hours ago, 900SL said:

What are you guys doing for a front dew shield/hood? Anything out there that works with a 2" filter installed in the front thread

I removed the ring holding the filter (l-extreme) and screwed in a 48mm extension ring. This holds the filter in place and acts as a dew shield as well. Also has the advantage of being able to screw the lens cap into it.

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  • 2 weeks later...

An earlier image of Sh2-115 taken in Nov 21 in NB and RGB through the Askar180. 

An area of hydrogen and oxygen deep in our night skies designated Sh2-115 (bottom right). I’ve shot this area before but this time I widened the field of view to capture the surounding flows of hydrogen and oxygen gas that sprawl across hundreds of lightyears of deep space. This ‘emission’ nebula lies along the edge of one of the outer Milky Way's giant molecular clouds, about 7,500 light-years away. Hot stars power the nebular glow by stimulating the atoms in the gas cloud which emit their signature colours. The cluster stars are likely only 100 million years old or so and are still embedded within Sh2-115.
The small blue ball type object is Abell 71, a nebula initially cataloged as a planetary nebula, it is now recognized as a small patch of dense hydrogen and oxygen emission. This took 23hrs to capture over several weeks due to the lack of clear skies. It is comprised of 21hrs of narrowband Ha, SII, OIII filter images each at 6 mins exposure and 2hrs of OSC RGB imagery to capture the colour in the stars. ASI294MC pro, ATIK460EX mono, iOptron Skyguider Pro mount, Askar FMA180 scope. Astrodon narrowband filters.

Clear Skies all. 

A2694E23-DD3C-4A32-9901-4DC469F5ED9D.jpeg

Edited by PadrePeace
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Don’t wish to hog the thread but the Askar 180 worked well with my ASI294MC in dual NB now that I have started shooting at 200gain to get over the Flats mismatch problem so many have with this sensor. This is 19hrs through the I-extreme Ha and OIII filter mounted on an AzGTI, with 6 min exp. 
 

 

04272408-C846-43FC-B3D5-5D24BD5605EA.jpeg

Edited by PadrePeace
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  • 2 weeks later...

Amazing images Padre. 

I'm pretty much ready to roll with my OSC set up now, hoping to get out in the desert soon and some bortle 2 skies 🤩

If the wind holds off I'll give it a test run this weekend in bortle 7 Khobar using a duoband NBZ filter.

What exposure would you OSC guys recommend for the Rosette? I have a new 533MC courtesy of FLO and will be using 110 gain and ASI Air Pro, the NBZ cuts a lot of light.. 3-4 minutes?

 

IMG_20220222_081409.jpg

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I've been looking at this thread with interest as I'm thinking of getting this astrograph. Reading the posts and looking at images of setups I'm still not quite clear how to mount it on an EQ mount and attach a guide scope/camera for guiding.

I'd be grateful for some pointers.

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52 minutes ago, LaurenceT said:

I've been looking at this thread with interest as I'm thinking of getting this astrograph. Reading the posts and looking at images of setups I'm still not quite clear how to mount it on an EQ mount and attach a guide scope/camera for guiding.

I'd be grateful for some pointers.

Depends on the rest of your setup to be honest. If you have an osc dedicated camera and off axis guider makes lots of sense. 

In essence there are two red tube rings that attaches to a small plate with a 3/8 inch camera tripod screw. Just get a vixen bar and screw that plate to the bar. 

Edited by Adam J
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I managed to get some frames before the condensation stopped play. Very noisy though. Seeing poor with humidity and dust here

 

Weathers now back up to 20+ so I'll hold on the dew heater for 10 months :)

Bortle 7+, way to go yet. 2 minutes appears to be too much looking at the number of clipped stars.  There's a 533MC exposure spreadsheet on CN that indicates 45s to 1 minute for my set up and location

662687312_rosetteCalibrate2AF.thumb.jpg.2f2bc4a018095c7e7d4e8ef36def7207.jpg

 

Edited by 900SL
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2 hours ago, 900SL said:

I managed to get some frames before the condensation stopped play. Very noisy though. Seeing poor with humidity and dust here

 

Weathers now back up to 20+ so I'll hold on the dew heater for 10 months :)

Bortle 7+, way to go yet. 2 minutes appears to be too much looking at the number of clipped stars.  There's a 533MC exposure spreadsheet on CN that indicates 45s to 1 minute for my set up and location

662687312_rosetteCalibrate2AF.thumb.jpg.2f2bc4a018095c7e7d4e8ef36def7207.jpg

 

Ok for a first shot. What filter are you using? 

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On 24/02/2022 at 05:57, 900SL said:

Had my first run in with dew last night, didn't expect that in the desert but I'm not far from the coast, 85% RH and dew all over my filter and objective

 

Recommended size for a FMA180 dew heater?

A two inch eyepiece dew band will do the job. 

https://www.firstlightoptics.com/dew-prevention/lynx-astro-15cm-dew-heater-strap-for-125-2-eyepieces.html

Adam 

Edited by Adam J
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On 22/02/2022 at 07:36, 900SL said:

Amazing images Padre. 

I'm pretty much ready to roll with my OSC set up now, hoping to get out in the desert soon and some bortle 2 skies 🤩

If the wind holds off I'll give it a test run this weekend in bortle 7 Khobar using a duoband NBZ filter.

What exposure would you OSC guys recommend for the Rosette? I have a new 533MC courtesy of FLO and will be using 110 gain and ASI Air Pro, the NBZ cuts a lot of light.. 3-4 minutes?

 

IMG_20220222_081409.jpg

I like the way you have set things up, how are you connecting the guide scope to the scope?

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5 hours ago, Adam J said:

Ok for a first shot. What filter are you using? 

NBZ duoband IDAS. I've noticed the blue channel is where most of the noise is on Siril

 

3 hours ago, LaurenceT said:

I like the way you have set things up, how are you connecting the guide scope to the scope?

I use a Neewer nodal slide. It has an Arca clamp one end to hold the Askar ring base, and the ZWO guide scope is attached to an Arca clamp. I'll get photos later

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1 hour ago, 900SL said:

NBZ duoband IDAS. I've noticed the blue channel is where most of the noise is on Siril

 

I use a Neewer nodal slide. It has an Arca clamp one end to hold the Askar ring base, and the ZWO guide scope is attached to an Arca clamp. I'll get photos later

Duel narrow band filters don't let much if any blue channel through although it changes from sensor to sensor. I would normally use super pixel mode in stacking and then remove the green and red channels. Then process separately and recombine. 

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14 hours ago, LaurenceT said:

I like the way you have set things up, how are you connecting the guide scope to the scope?

Hopefully you can work it out from these. My favourite farkle so far is the hood, it consists of three parts including a filter holder. I've mounted it here on a Sirui tripod head, I don't use that on my tracker. The nodal slide is held in an Arca clamp on a pan head on my Fornax Lt

IMG_20220226_080310.jpg

IMG_20220226_080227.jpg

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4 hours ago, LaurenceT said:

Thank you so much for taking the trouble to post those clear images. My only concern now would be mounting the nodal rail on my Az GTi mount with a vixen style clamp.

It won't work with a vixen clamp, unfortunately. 

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14 hours ago, Adam J said:

Duel narrow band filters don't let much if any blue channel through although it changes from sensor to sensor. I would normally use super pixel mode in stacking and then remove the green and red channels. Then process separately and recombine. 

That seems to be quite straightforward in SiriL. Theres a YouTube tutorial on same, using RGB extraction of the OSC and recombination with red as both a luminance layer and red channel, and green as both green and blue. SiriL also now has a script for Ha Oiii extraction on preprocessing. I'll have a play around. Realistically from my location I need more hours data too

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How do I fix the coma's on this thing? the 220 is horrible so it's a 180 scope atm, I put a lp filter on the front and I think I made it worse, tried the rosette and only a few stars in the center are perfect circles. I'm not using any of the extention tubes just the reducer and reducer extension tube.

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20 minutes ago, Quetzalcoatl72 said:

How do I fix the coma's on this thing? the 220 is horrible so it's a 180 scope atm, I put a lp filter on the front and I think I made it worse, tried the rosette and only a few stars in the center are perfect circles. I'm not using any of the extention tubes just the reducer and reducer extension tube.

Would be useful to see a picture of both the image / stars and how you have the scope setup? For the record it's not designed to be used at 220mm for imaging. You can only image with the corrector reducer. 

Adam

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42 minutes ago, Adam J said:

Would be useful to see a picture of both the image / stars and how you have the scope setup? For the record it's not designed to be used at 220mm for imaging. You can only image with the corrector reducer. 

Adam

I'm out with it now, i hope you can see what's going on, i just made myself a hood because the neighbours are huge light polluters and they aren't the negotiable type. The pics are in fits format so I can't see them until I start loading them into a stacking software, I'll copy an image over in a bit. I use my ed80 as a mount for the 180, it's embarrassing but i only have a neq6 and i can't put it on it's own it's too light. but thats another problem on it's own to sort out at some point.

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DSC_0015.JPG

Edited by Quetzalcoatl72
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I've included a 5 minute exposure one at the start of my session and one recently after I've messed around with it, I'm starting to think it's amp glow too, that red light on the corner seems to have sucked it out of the rosette since it was fine at the beginning. However the 533 is designed to have no glow a all.

2022-02-27_20-11-51__-10.00_300.00s_0003.fits 2022-02-27_22-13-58__-10.00_240.00s_0019.fits

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I think you're using the wrong spacers between the camera and the flattener. The one with 3 screws is designed for an eyepiece, not a camera. I'm pretty sure this is causing the coma.

This is what you need to reach 55mm of back focus:

image.thumb.png.fc1bd70a8befe4933fd3a7fb0914de32.png

image.png.1c324383a72f88e848a9959ffbaffb1a.png

Tip: you might want to place the 21mm before the 16.5mm spacer, unlike the diagram above. It will work better with the Askar's rear T2 mount!

Some documentation:

http://www.askarlens.com/index.php/class3/186.html

https://astronomy-imaging-camera.com/tutorials/best-back-focus-length-solutions-55mm.html

Edited by Space Oddities
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33 minutes ago, Quetzalcoatl72 said:

I've included a 5 minute exposure one at the start of my session and one recently after I've messed around with it, I'm starting to think it's amp glow too, that red light on the corner seems to have sucked it out of the rosette since it was fine at the beginning. However the 533 is designed to have no glow a all.

2022-02-27_20-11-51__-10.00_300.00s_0003.fits 17.27 MB · 3 downloads 2022-02-27_22-13-58__-10.00_240.00s_0019.fits 17.27 MB · 2 downloads

yeah thats totally wrong.

See the reply from space oddities.

Adam

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