UCzerw

18 hours ago, Spile said:

Czy nie byłoby prościej nosnikiem celownika z celownikiem?

I bought a new one, I tried. It rocks in all directions.

in addition, the wire of the cross fell out and was lost

I made my own cap, no reduction.

I don't know if I'm doing it right. I'm a goddamn perfectionist ...

Hi. I wanted to set up the secondary mirror using a webcam, but something is probably wrong.

I think it's a focuser/draw tube (I'm not sure about the nomenclature). Are there any ways to fine tune this?

Hello. Recently, my mount has been working with resistance in both axes. As far as I have tweaked the DEC, I have a problem with the RA.
I just can't match these items.

If I hadn't taken the assembly apart myself, I wouldn't have believed that these parts fit.
Has anyone had a similar problem? Any suggestions?

You have very advanced setups. Asiair and astrohubs are dropping out for now. But my friend is supposed to make a hub for me and I think I'll think about 3D printing a handle for this.

Hi! I'm mature for a serious approach to guiding. Narrowband requires long exposure times, and properly arranged cables can make it easier. Exactly, properly arranged cables, but how?

At the moment, I combined 3 cables into one (guider, dslr, dslr battery).

The heaters have usb inputs so I decided to connect them with a hub and lead them out with one cable. I don't know where to attach the hub yet, but it will be rather on telescope.

Maybe someone will show their setup and cable management methods?
I will be grateful.
Best regards

I have dilemma. The Sbig ST-2000XM seems to be outdated. However, I live in a city so I have a lot of light pollution. Supposedly, mono cameras are better in such conditions? I wonder if it is worth using such a budget solution at the beginning? I am currently using a Canon 600D with astromod.

Unfortunately, Nikon does not support BULB mode on the computer. I had the same problem with my D5100. The intervalometer is necessary for longer exposure times.

In less than 30 seconds, there is little point in guiding. Although it is worth training in guiding to make it easier in the future.

Edit: what about reducer/flattener? 

11 minutes ago, bottletopburly said:

Nice article here I just got my lad to do a spreadsheet based on a formula posted on Apt forum  

https://www.myastroscience.com/calculatedithering

I found it. But I have considerable gaps in knowledge. After graduation, I have to work hard on the theoretical foundations of astrophotography.
Excel show to set APT to 2

I'll try next clear night.

Thank you gentlemens.

1 minute ago, bottletopburly said:

Yes change dither distance to 6 for a maximum dither of 16 see how that goes 

And leave dither scale 10 in phd2?

I think only one filter has been removed. It is not a full spectrum mod. I received one filter as a souvenir, and the person who made the modifications thinks that there is no need to remove two filters.

But soon the Moon comes into play, and so far I'm not using filters. Besides, I might have a problem with that. SkyWatcher is smart . Their reducer does not support filters 😅

I'll try to increase the dithering. I just don't understand these calculations. If I have a 1.3x scale difference (image / guide scale). In phd2 I have dither scale set to 10. In APT I have set to 1. So that's 13 pixels. If I change dither distance to 2 in APT, I will get an offset of 26 pixels. Setting APT dither to 7 will give me over 70 pixels.
Am I counting something wrong? There is any "sweet point" how many pixels should I set for dithering?

• a single light frame
• a single bias frame
• master bias
• final stack

Hope everything works.

59 minutes ago, alacant said:

Hi

Try a bigger dither with windsored sigma clip at e.g. 3 3. The debayer looks like it's left a grid too. Try RCD.

If you're not keen on spending time processing (I'm not!) I think you're gonna have to get an astro camera, use your Nikon or simply take more frames with the 600. Otherwise, it's easily corrected.

Cheers

 

Thanks. I used the latest version of Siril. A few days ago it was published and I can see that the RCD is set by default.
Damn white nights. Terribly short, but now the moon is coming, it will be a bit of a rest.
I'm seriously starting to think about a cooled camera, I have to look for information that is worth choosing at the beginning.

I just wonder if this noise on the red channel is normal? Single light frame, auto stretch.

Do you mean dithering distance in APT? I didn't change much in apt. Only time, because sometimes the mount goes crazy

23 minutes ago, bottletopburly said:

What’s your guide scope Fl , imaging scope fl, imaging camera pixel size and guide scope pixel size ?. 

Gude scope 60/240mm, guide cam 3,75 upix

Imaging scope 72/420 + 0,85 reducer;  camera 4,3 upix

Scale 1,3x probably 

31 minutes ago, bottletopburly said:

What programs are you using to dither out of interest 

PHD2 and APTool (older version)

1 hour ago, bottletopburly said:

How many pixels are you dithering , try a dither of at least 15 pixels you have walking noise so possibly not dithering enough .

I started with 10 pixels. Maybe more frames with shorter time will be a better option?

Still the same problem, even with dithering.... Some "smudges" of noise.

OK thanks. Previously, I only did preprocessing with biases for flat frames and pre processing for lights with stacked darks and stacked pre-pocessed flats.

I will try as you say in Siril. Yesterday's attempt to dither every 3 frames below. From DSS (no dark frames, only biases and flats).

The background looks good I think. I have to extend the time between dither and shot, because the stars after dithering were not perfect. And I'm still struggling with mount and backfocus. 

23 minutes ago, alacant said:

Hi

Yes. Please see here. 

Having tried DSS and Siril for stacking, IMO Siril has the best stacking. There's a nice comparison between apps here.

Cheers

 

Thank you so much. 

But to be sure, I will ask... Should I use bias frames for lights before stacking in pre-processing? At Siril, I only use biases frames for flat frames in the pre-processing. As they show in tutorial. 

Will I find a better tutorial somewhere? Because from what I can see they are using Winsorized Sigma C. I don't know how much different that is.

2 hours ago, edarter said:

You could also try different sta king software, I had awful trouble with banding from my 600d (though horizontal, not vertical like yours) when stacking with DSS. At about the same time I made the jump to APP and the banding immediately disappeared.

I know you aren't using DSS but the stacking software is something else to consider as a cause. 

I tried this material in DSS as well. Maybe it was slightly better.

Does dithering require any special stacking options?

2 hours ago, AstroNebulee said:

Like alacant said don't bother with darks, I have a Canon 600D and 72ed ds pro and don't bother with them, I just take my light frames as usual then 20 bias and flats, jobs a goodun, no dithering for me 

I made a stack with no darks (and no dithering) below. The effect is still weak. But I found the histogram strange/ragged after auto stretch.

I checked on older material from my Nikon, without mod. The histogram was fine. And noise. 

And my earlier attempt with this Canon. Same stacking methods as M101.

1 hour ago, AstroNebulee said:

Which mount are you using and scope? 

HEQ5, SW Evostar 72 with reducer/flattener 0,85

1 hour ago, david_taurus83 said:

What temperature was it when you took this? Did you flip out the screen?

I opened the screen while taking phots. APT shows lights at 23-24 degrees Celsius.

1 hour ago, alacant said:

Hi

Not really enough information, so some general stuff...

Best without dark frames on a 600d.

Dither between each frame.

Don't forget to use bias on both light and flat frames.

Stack with a clipping algorithm.

Take more frames.

HTH.

I use exactly this algorithm. With bias, darks, and flats. Today I want to try dithering. I may succeed.

1 hour ago, Seelive said:

As mentioned above, the sensor temperature can make a big difference to the noise and keeping liveview on will increase the internal camera temperature. You can download EXIFLOG from http://www.covingtoninnovations.com/dslr/exiflog.html that will show you the temperature of the DIGIC chip when the image was taken (not the actual sensor temperature, but probably won't be far off).  Ideally your darks and lights should show the same temperature. If their is a large difference (>5°C?), try stacking without the darks.

With my 200D I take at least 80 x 180 sec images to get the noise within (my) acceptable limits but that may be due to my Bortle 5-6 sky.

Darks EXIF

Light EXIF:

Biases EXIF:

Hi! 

I am starting an adventure with a Canon 600D with an astromod. And I noticed a terrible noise. Below a stack 30 frames (from Siril, zoom and auto stretch) of 180 seconds, iso 800 with calibration frames.

I checked earlier photos taken with Nikon without astromod. There has never been anything like this.
Where does it come from? How to fight it?

1 hour ago, michael8554 said:

What kind of filter did you have in mind ?

Any filter that reduces light pollution. It's probably because of LP my subs are so bright / milky?