MarsG76

Awesome details.

1 hour ago, Aramcheck said:

PS: I'm aware that the 120MM may not be the best, but current budget didn't extend beyond the OAG & Helical focuser.

Theres nothing wrong with the 120MM.. I use the 120MM mini and I'm very happy with it.

1 hour ago, Aramcheck said:

Also - last night after focusing the main camera/scope, the guide camera distance didn't seem to make much difference to the view of the star in the guide camera or star profile image in PHD2. I understand that it should be set parfocal with the main camera, but how critical is the distance & how do you tell if I can't see it very well in PHD2?

I find that there is not much tolerance at all... I find that a guide star can go from a round point to a oval within a guide cam movement of 1-2mm... 

1 hour ago, Aramcheck said:

if I want to rotate the whole assembly to either obtain better target framing, or to find a guide star, will I have to redo the guide calibration?

Yes you will have to re calibrate guiding because the angle of the camera will change and that will impact on what angle PHD2 sees as north/south and east west... 

27 minutes ago, Ratlet said:

Beautiful image.  Makes me wish the earth rotated pole to pole.

You peeps have plenty of objects we're missing out on down here.... but thank to platforms such as this one, we can share the view of the celestial wonders beyond our horizons.

On 08/06/2022 at 13:50, Rodd said:

This target is so much better in NB. Well done. 

I agree but also think that most nebulae can look better imaged in NB because there is more flexibility/possibility to bring out subtle detail in processing than with wideband.

How cool... How good are the pictures taken with it?

25 minutes ago, Yoddha said:

Hello,

PAPS - Polar Align via PlateSolving is not showing accurate results, so the small update APT 4.01 is released to fix that. We have used the opportunity to include a few more fixes and minor new features.

Please update your APT to be ready for the next New Moon

The full list of novelties is available here:
http://www.astrophotography.app/new

Hi Ivo,

How sure are you about this? How much inaccuracy?
When I ran a test using PAPS, initially PHD2 reported a PA error of around 4 arc-min in 10 minutes of measuring before I ran the PAPS procedure... After I polar aligned with PAPS, PHD2 reported 0.7 arc-min also in 10 minutes of measurement...  Could there be a difference with being in the Southern Hemisphere as the PAPS initial release did not work down here?

Mariusz

Only 2 hours??!?!?... wow..

That is a fantastic image...

Hi Astroexplorers,

Sharing my first frame of my WIP mosaic of the "The Fighting Dragons".

This is NGC 6188 or Gum 53 (AKA The Fighting Dragons), an emission nebula located about 4,000 light years away in the constellation Ara.

I imaged this with a QHY268M through Baader 7.5nm Sulfur II, Hydrogen Alpha and Oxygen III narrowband filters, using a cheap (it was cheap when I got it before all astronomy gear sky rocketed) doublet 80mm refractor at F6.25 (500mm focal length) and tracked on a "hypertuned" CGEM mount.

The total exposure time spent on this frame was 16 hours and 40 minutes.

I'm slowly exposing the other frames/plates for the mosaic as I get a bit of clarity... I was exposing some SII data as I write this and had to run out to close my observatory when I heard a sudden down pour... literally went from clear to a downpour in less than 5 minutes... nuts!

Clear Skies,

Mariusz

On 17/05/2022 at 17:37, newbie alert said:

So the 4.0 is the latest stable version or a beta? 

Must admit to having issues with the betas so I went back on the stable versions

3 hours ago, Yoddha said:

Hello,

No problems reported in APT 4.00 so far  Don't forget to update your imaging computer for the next session  

Meanwhile we are forcing the work on the next beta...

I can vouch for that, after a few full nights of imaging, APT 4.00 was rock solid.

21 hours ago, CCD Imager said:

You would be left with just M81

Wouldn't be that bad. Looking at the flares, you wouldn't need to crop out much more than when I do with almost every image on my cheap refractor to get rid of most of the edge star distortion.

In actual fact cropping out your flares would frame it quite nicely.

9 hours ago, wimvb said:

The pattern can be caused by reflections off chip edges, bonding wires or what have you not, within the camera and close to the sensor. Basically any light that can make its way into the sensor chamber.

This was suggested by Adam Blick in one of his youtube videos.

10 hours ago, CCD Imager said:

Maybe it is the street light then, would fit with the green colour of the light intrusion.

Adrian

I know it's easily removed but personally I like the flare in the image... I wouldn't want all of my astrophotos to have a flare but this one is OK. Something different from my past images of M104.

4 hours ago, CCD Imager said:

Wim, 100% agree, any light incursion can be scattered within the optical path, probably close to the sensor, there are several potential reflective surfaces. The problem is identifying its source. Here is an image I had fun with! Work out the problems here

Yawzah.... initially I'd guess stacked filters and internal reflection??

4 minutes ago, CCD Imager said:

The fact that it is not in your Antennae image suggests its not  a fixed light source on your imaging rig or related to the camera, so a source close to your camera that doesnt move could be the culprit or as Wim suggested  a star just outside the FOV. I looked at Stellarium and there arent really any bright stars close by that makes me wonder if this is the cause, but I think its still the most likely. A street light I think is unlikely as that would produce a much more diffuse gradient across the image. The fact that it is green suggests a "light pollution" source rather than a star. 

Thesee artefacts are a pain in the a**** and it is always best to find their source, but to edit, I would remove stars with Star Xterminator or Starnet then easily clone stamp or use the spot healing brush tool in Photoshop.

Adrian

The antennate galaxies were imaged with a dew shield, wind gusts picked up during the luma exposure of the sombraro when I removed the shield.

8 hours ago, CCD Imager said:

I agree, nice images, M104 is only just imageable from the UK! What was the cause of the green incursion on the Sombrero image?

Adrian

3 hours ago, wimvb said:

Reflected light from a bright star outside the fov. The reflection extends all the way to the galaxy.

Possible that it's caused by a out of FOV bright star, but more likely it's from a street light. At one point during the tracking the scope was angled where a street light was in that direction and about half of the subs had this flare every night.

I had to remove the dew shield from my SCT because there were slight wind gusts which were caught by the shield and caused a bit of a vibration, ruining subs.. as you can imagine that at 2000mm FL it doesn't take much to render a sub unusable... I have dew heating which controlled the condensation on the corrector but external light flaring does (and did) occur frequently in the past when I removed the dew shield.

Thats disgusting behaviour... what a some dishonest people are doing is, after this oil leak issue has been shown to have been very common, they're palming off the oil leak problem onto unsuspecting buyers and getting the QHY268 series that doesn't seem to have the oil leak problem. They knock off a few hundred dollars from a new price and just go and get a new QHY which happens to be a few hundred dollars cheaper. 

Looks like cleaning it is your only option... if you're handy with small/jewelers screw drivers than it doesn't look like a difficult job... Look up "Windy City Astronomy" on YouTube, he goes through cleaning this kind of oil leak on one of his videos.

Problem is that this oil leak has returned for a number of astroimagers who had it cleaned or cleaned it them selves, so it might return, that said, I'm sure that there is a limit to how many times it will return.

22 minutes ago, ONIKKINEN said:

Im thinking of using a helical microfocuser between the camera and OAG for peace of mind. Id rather not deal with the headache of figuring out the exact shims required to keep it parfocal.

That sounds like a good plan, just be careful about how much space you create between the OAG and the camera as there is a limited amount of distance that you'll be able to pull out of the OAG before using extenders (which is not ideal).

2 hours ago, david_taurus83 said:

Interested as will be doing the same in the future. I would bin 2x2 though.

1 hour ago, ONIKKINEN said:

If it works for 2000mm FL then sounds good for my plans.

Yes I BIN2x2 my 120MM mini.... As far as imaging goes, I dont see my self going back to guide scope again... once the OAG is setup as running... and thats not that hard to do one you do it a few times... takes care of flexture and you're guiding at the same focal length as imaging.
One important thing to note is make sure the OAG is parfocal with the camera, half the problems in not finding a guide star was that the OAG was not in exact focus, limiting to the brightest stars if not completely eliminating seeing any of them.

I'm using a ZWO120MM mini with a OAG on my C8 at 2032mm focal length, and I don't remember having a situation where I didn't find at least one guide star within the search area.
On my 500mm focal length refractor, I don't think I ever seen a starless field. 

18 minutes ago, vlaiv said:

No (not yet, expecting to get one any time now :D), but I do have unused B-mask that I can use by covering angled grating part with something and 4" F/10 achromat :D.

Do it... and tag me on your posts about it.

24 minutes ago, vlaiv said:

Well, all refractors have this issue - question is - how much of it do each of them has

If we could measure it without expensive lab equipment like monochromators and such - I guess it would at least be interesting / educational.

I think that proper shape for measurement is simply half grating looking like this:

(just half of aperture covered by grating and other half clear).

This animation shows why spike moves from one side to other as focus is reached and passed:

Further from focus image resembles more that of aperture itself and as it focuses - it comes to a point. Similarly - if grating is just to one side - it will switch sides in out of focus image - that means it should pass thru a point in focus - much like horizontal grating does in above animation (starts on one side and then moves to other as it defocuses).

 

Now this looks like a experiment calling out for attention... have you got a 3D printer? If so, print the mask and give it a try.

5 minutes ago, vlaiv said:

I did not realized it until I found the images on the link I provided.

Now I'm thinking that it can be somehow used to visualize / measure color correction of refractor telescopes?

Yes thats true... although if a Takahashi has this issue than it must not be a big deal... chromatic abberations are definitely of no concern when imaging with a mono camera and the telescope is refocused for each filter.

On 15/05/2022 at 06:05, vlaiv said:

It looks like this might be effect of color correction of objective lens - imaged with full spectrum mono camera.

https://www.cloudynights.com/topic/665210-question-about-using-a-bahtinov-mask/

Bahtinov mask acts like very low resolution diffraction grating and spikes are in fact low resolution spectra.

In above image multiple orders can be seen in each spike.

Position of each spike will depend on focus, and depending on color correction of telescope - focus can shift with wavelength creating little curls or at least waves.

You are not seeing that colors are affected as you are using mono camera.

 

 

I think you nailed it... thanks for that link....
Images in the link definitely resemble what I was seeing... and I think that I didn't see this phenomenon before because I was focusing at a lower resolution image BIN 2x2 or 4x4... now I did it at BIN 1x1 with the 1:1 view centered in the frame and it all became curly.

I did a experiment today and again I saw the culrs but not at BIN 4x4.

Nice work.

On 15/05/2022 at 06:26, The Admiral said:

How do you focus? Could they be oscillations of the scope after focusing by hand? Presumably the amplitude of the oscillations wouldn't need to be large to give that effect.

Ian

Edit. On second thoughts, I don't think you'd get that! 🙄

 

 

 

 

Definitely not oscillations.... I think Vlaiv is on the money...