807 replies to this topic

[ATM57]

In that case, you really should calculate what aperture is required to achieve an unobstructed equivalent to 6.1, maybe 6.2"

Huh? Please forgive my lack of understanding. This old guy can be a bit slow sometimes, but you have lost me So... How would I calculate a 6.2" unobstructed aperture for a C14 with a 4.5" secondary obstruction?

 

Original poster: Apologies   I'm not trying to hijack this thread.

[06AwzIyI]

I was assuming it would work, but I guess not based on your response. I'm not the guy doing the experiments with a c14. Not to mention I'm being satirical, to stir the pot so to speak. So tell me, could you bump it up to say...4.6 inches and still get a good image?

Or alternatively, couldn't you center the inlet over the secondary and calculate the obstructed surface area of the mirror to match the equivalence of an unobstructed 6"?

Or hell, have multiple smaller inlets. Wouldn't two 3" inlets opposite each other do the trick?

Edited by 06AwzIyI, 01 November 2020 - 06:27 PM.

[ATM57]

OK. Now you're making me fry what few brain cells I have left: 6.2" = 30.19 sq. in.

 

If I calculated right, two apertures @ 4.38", which the mask can hold, would equal 30.19" of area. The separation should also increase the resolution since the two separated 4.38" apertures (@9.25") would result in a interferometric telescope with a theoretical Dawes resolution of 0.5 arc seconds. (correction requested)

 

You have now caused an astro-itch that I will have to scratch.

 

Again, my aplogies to the original poster.

 

Now... I need to take a nap...

 

Edited by ATM57, 01 November 2020 - 07:49 PM.

[WarmWeatherGuy]

The area of a circle is pi * R^2 or 0.25 * pi * D^2.

[ATM57]

The area of a circle is pi * R^2 or 0.25 * pi * D^2.

I understand the equations. What did I miss?
 

[WarmWeatherGuy]

I understand the equations. What did I miss?
 

Please excuse my brain fart.

[ATM57]

Please excuse my brain fart.

Not a problem. I'm finding that the older we get the more we have them... from both ends.  

[moonwatching ferret]

 A lot of great images coming from even small scopes but something tells me i had beter hold on to my 16 inch ecven if i have to live in it. nice work 6 inch scope owners

[rhombus]

More than 6".

 

 

By 2.6 mm - I think we can allow it!  It is a terrific image, rhombus.

 

 

Hmmm, just think at the fact that many telescopes on this thread under 6" have obstruction. This 155 mm should "compete" with 180-190 mm obstructed. So, it's not a fair play. If the thread is "6" or less", let respect this.

 

 

That's a fair enough opinion, ROursamajor. I'm not concerned, though - it's 6.1 inches, and this isn't a competition.  I also think 6" SCTs could produce equally good images under the right conditions.

 

Thank you. I have to say, looking through these small bore threads over the years is what made me dream of owning a 6" class APO for both planetary viewing and wide-field imaging. I used the Jupiter, Saturn and Mars threads to try to get a realistic idea of what was possible out of a 5-6" refractor. These threads are such a great resource for anyone researching scopes.

 

I realize its 0.1" over 6", but in the spirit of what it means to have what is still considered a small bore scope (for planetary work), I want to give back to the thread that I found so helpful. I would hope that others in the future can see all the great images everyone posts and realize that you dont have to have a huge scope to get satisfying planetary views. Not to mention that many dont have the steady skies to take full advantage of a huge planet killer scope, and necessitate all that goes along with using one.

[b34k]

Got a new camera last week figured I'd submit an updated image.

Skywatcher 150p Dob
GSO 2.5x barlow
Astromania ADC
QHY 5-III 462c

 

Captured 39,837 frames with FireCapture 2.7 beta

Stacked at 70% with AS3, Drizzle 3.0

Registax wavelets

Photoshop levels and resize

 

[Shawn12345]

Meade ETX-90, 2.5x barlow, ZWO ASI-120MC  

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[Shawn12345]

Meade ETX-90, 2.5x barlow, ZWO ASI-120MC

About two hours' rotation. 

 

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[Thomas A Davis]

Here's one from last night with the 120ED with a 5X Powermate (4500mm FL) and ASI224MC.  Best 15% of 4740 frames.

 

Tom

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[Euripides]

My best capture of Mars so far.

 

FireCapture : 5 x 2' videos
ROI=344x264
Shutter=6.000ms
Gain=300

 

PIPP (Join mode):
Total input frames: 99883
Frames discarded by quality: 74913
Total unique output frames: 24970
Total duplicated output frames: 18727
Total output frames: 43697

 

AS!3 : Best 10%, Drizzle x1.5

 

[Sassenach]

Hello all,

 

I took this at the weekend

 

Setup was 6 inch f/5 Dob (Orion Starblast 6), iPhone 7S, Orion Steadpix EQ, TX x3 Barlow, ES55 6.5mm

Processed using PIPP, Autostakkert and Registax

 

I live in Munich city centre, so the light pollution and low altitude of the planets is always a challenge

 

Best,

 

Andrew

 

[RickD_99]

Mars on 03NOV2020 at 02:54 UTC. I used Steve's (AKA @WarmWeatherGuy) image processing tips from the following thread:

 

https://www.cloudyni...s#entry10565352

 

Also got rid of some pesky leftover halos using GIMP and Darryl's tip from the following thread:

 

https://www.cloudyni...es-nov-3rd-5th/

 

Equipment

 

Celestron DX130AZ 5" (130 mm) f/5 reflector (this is a recently introduced beginner scope incorporating StarSense smart phone guiding tech)

 

Above scope collimated with Orion Lasermate Deluxe II Collimator

 

Celestron AVX Mount

 

ZWO UV/IR cut filter

 

Tele Vue 3X Barlow

 

ZWO ASI290MC

 

Software

 

FireCapture 2.6.08

PIPP 2.5.9

AS!3 (stacked best 5% of 27278 frames)

Registax 6

AstraImage 5.5.8.0

GIMP 2.10

Image and FireCapture log file are attached....

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•  2020-11-03-0254_6-L-Mars.txt   897bytes   1 downloads

[rnyboy]

Weather last night was about the best I've had this fall but even with the better seeing conditions Mars has moved far enough away from last months opposition to be noticeably smaller and with lower brightness.  Here's a side by side of the same hemisphere face of the near opposition Mars and the one from last night.

 

 

Because the seeing was good I decided to take a 60 sec (128 fps) SER capture, at f/25 with my 6SE/385mc, every 15 minutes for a little over three hours (phew!) and today I turned those into a 10s video of Mars rotating about 45 degrees on it's axis.  I did the typical AutoStakkert/Registax6 bit and then manually rotated the field rotated images so the south pole was "south" and then used Giphy to create the gif.  (First time making a gif too.)

 

Edit:  It turns out I had to remove the gif because it exceeded the 500kb limit (I didn't check and it was 547kb).  It would take too much effort to crop and get the 14 images realigned so I removed the gif.  Here's a link to it...

 

https://giphy.com/gi...cce5umuI86KqtPa

Edited by rnyboy, 10 November 2020 - 05:03 PM.

[metagawd]

Mars, Nov. 16th, 2020

 

-ES FL-AR102 102mm refractor
-SkyWatcher Az-GTi
-Sony IMX291 Camera

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[JEntwisle]

Mars taken on the 10th from near Leeds, UK

130 mm meade reflector with a modified logitech c270 and a 2x Barlow. 

Stacked using autostakkert and processed using registax. 

 

Not sure whether I'm overprocessing but it obviously doesn't look fantastic.

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Edited by JEntwisle, 18 November 2020 - 02:04 PM.

[mjsangster]

Mars Nov 19th, C6, 2.5x Barlow ZWO ASI290mc camera with IR cutoff filter.

 

[Sassenach]

Taken with an Orion Starblast 6 inch f/5 and an ASI462

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[Tulloch]

I had the 6" out in preparation for the upcoming conjunction.

 

Celestron C6" SCT on Evolution mount, TV 2.5x PM and ASI224MC, best 5000 frames from 45000 total. Stacked in AS!3 with 3x drizzle, sharpening in R6, post processing in PS Elements, shown at 2x captured size.

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[Woj2007]

My memories from 2020 opposition: 28th October, 1st, 7th, and 21st November.

Taken with ASI 462 & 2.5x Barlow attached to Mak 150

I always got this rind artefact around Mars, that needed postprocessing. This thread gave me answers why:

https://www.cloudyni...artefact/page-6

(a proper link to the report):

https://skyinspector...-edge-artefact/

 

 

And the last one from 12th January:

Edited by Woj2007, 14 January 2021 - 05:39 PM.

[HarveyDeckAstro]

Mars taken two hours apart on Jan 20, 2021. The aim was to see the rotation to confirm that the features are real not artifacts. Indeed, I can make out the direction of rotation!

 

NexStar 130 SLT (5'' Newtonian), ASI462MC, AS3, sharpened in PhotoShop.

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[HarveyDeckAstro]

Mars on Jan 21, 2021 11 pm UT. Finally captured this iconic markings on Mars!

 

NexStar 130 SLT, ASI462MC, ~ 270 fps, AS3 1 percent stack, PhotoShop.

 

Edit: Still learning, just getting used to Registax 6. With it the image seems a bit better (image updated).

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Edited by HarveyDeckAstro, 22 January 2021 - 07:11 PM.