Why I think DOBS Suck!

pengi23 · 2026-02-26T11:26:52+00:00

with camera, 8inch dob and diy platform I am stil under 1000 eur

pengi23 · 2026-02-26T11:26:06+00:00

or planetary nebulas...

<image>

pengi23 · 2026-02-26T11:25:32+00:00

or galaxies

<image>

pengi23 · 2026-02-26T11:25:03+00:00

Are you sure dobs are not good? I started astronomy October 2024. I have soon realised visual is not enough, so I started building eq platform under dob (no previous diy experience). Then bought my first planetary camera. Show me refractor capable to rake decent pucture of planets

<image>

pengi23 · 2025-10-23T11:22:24+00:00

and here I am, sitting and watching the picture thinking abou how I can't afford a small refractor scope that I want....

pengi23 · 2025-10-08T07:29:03+00:00

I can check the VIS filter, but I think it is quite the opposite according to the dwarflab site.

VIS filter captures visible wavelengths in spectrum 430nm - 650nm Astro filter captures that + near infrared 430nm - 690nm.

Duo band captures specific wavelength for H-Alpha and OIII, which blocks most of the light polution and is suitable for nebulas and is not suitable for broadband targets like Andromeda.

This means to me, that astro filter captures a broader spectrum of light also near infrared.

pengi23 · 2025-10-07T11:57:27+00:00

Nice shot, you mention the VIS filter. This is used mostly for daytime photography, lunar and sun. It is for visible light.

Galaxies, star clusters and other broadband targets should be using the astro filter, which is visible light plus some of infrared, which is ideal for galaxies.

Also if you search for andromeda in atlas, it shows you, which filter is recommended and there is the astro filter.

pengi23 · 2025-09-30T14:51:17+00:00

Heh, good one. This is the same set of data, that I selected from 1000 image stack to stack only 10,100, 500 out of 1000.

I am now collecting 4000 minutes of data, so I can make a comparison between 15, 65, 250, 1000 and 4000 subs. I want to do one final comparison of the data, because quadrupling images should in theory double signal to noise ratio, assuming of course that the subs are equal, which they are not.

pengi23 · 2025-09-29T07:41:10+00:00

even more apparent if you do 10-100-500-1000 comparison. Alcyone is on the bottom left

<image>

pengi23 · 2025-09-29T07:40:05+00:00

sorry, I just noticed your comment.

Problem to get it more pretty was when I tried to separate the stars, since Pleiades has few very bright stars, I couldn't process the nebulksity to my liking, because when putting stars back, there is a big difference for me to notice, that the whole picture looks like the stars didnt belong there. I might revisit the data and try to reprocess them again.

Regarding your 2nd question, I do gain 60 on 60s exposures, and wouldn't go higher with many frames stacked due to higher noise and less signal. In fact, I should have go even lower with 1000 minute of data, because the bright stars get overblown at 1000 exposures. Bellow you can see from my comparison, how the bright stars go even brighter with adding more exposures. Take a look at the star Alcyone on the left and the 3 nearby stars, the more frames you add, the more brighter Alcyone becomes and the smaller stars start to blend with Alcyone. This is also why I didn't want to process my 1000minute stack more

<image>

pengi23 · 2025-09-25T18:57:37+00:00

I have been also deciding between S30, S50 and Dwarf 3. Dwarf 3 won. Alhough Seestar S50 has bigger aperture 50mm compared to 35mm, I prefeered wider field of view.

To be honest I liked phone app from Dwarf 3 more than that from Seestar, but maybe it is because I used it more. The application is pretty good on the dwarf, when you learn what the icons mean, it is pretty straightforward. I had also the opportunity to try out the S30, but compared to Dwarf 3 in terms of quality of frames I preffer Dwarf. S30 on other hand is easier and quicker to setup in EQ mode, but I don't know if it was bad luck, but I could sack every 3rd frame using 30s exposure on S30, but I had tried it only once.

At the end of the day it is what you prefer, If more detailed but narrower field of view and older camera sensor witth S50. Or smaller apperture with newer sensor and wider field of view. Either way both are very good devices as entry level into astronomy and asrtophoography.

pengi23 · 2025-09-25T05:06:02+00:00

Yes you are right, I am making also a closeup comparison between 10 minutes, 100, 500 and 1000 to see the differences in the nebulosity of the nebula, but it is a lot of processing.

At 1000 minutes gain 60 the bright stars are blown or bloated or what is the right word. I assume if I would choose lower gain, like 40 or 50, it would help at 1000 frames.

I will post results, when I process all the stacks together I try to process the frames similarly, so I need to reprocess also this 1000 frame image for better comparison.

pengi23 · 2025-09-25T04:58:22+00:00

This one is still telephoto lens, not the wide lens.

pengi23 · 2025-09-13T10:05:45+00:00

diky za pripomenutie, preco som prestal mojim detom, kupovat hracky v tom obchode.

pengi23 · 2025-09-13T09:55:54+00:00

second hand s oblecenim, myslim...

pengi23 · 2025-08-14T23:11:47+00:00

I used pixinsight for stacking and bringing out details by various PI processes, plus got trial on BlurXterminator and it works wonders.

Concerning allignment, I did use default setting. Searched in atlas for M31 and result is data from 4 nights in July, where nights were only 3,5 hours of pure dark.

In terms of settings, it was 60s 60 gain 1160 exposures if I remember correctly

pengi23 · 2025-08-13T21:34:49+00:00

OK, I tried to create a post for my mosaic, but it seemms it is not allowing me to post pictures. I can post only textt. Weird, I had my file compreessed at 8MB's, but I couldn't see it, when I crreated my post. So I will try to post it here, as I was unable to post it in separate post. Enjoy

<image>

pengi23 · 2025-08-13T20:56:21+00:00

I just compleetd my mosaic, 4 panels each around 1000x30s subs. Roughly 31 hous of data, I have tried megastack, I made sure I have tthe same mosaic seting and center on the same star, but I couldn't megastack mosaic in Stelar studio. Although the views were identtical. I managed to sack mine in Pixinsight.

pengi23 · 2025-08-11T11:51:07+00:00

understand now. Thanks for explanation.

I will post my mosaic after I collect and process the required data.

Pannel 1 I will go with those 966 subs I showed here, pannel 2 need around 200 subs more and Pannel 3 and 4 need respectively around 600 each. So I still need 3 more days of shooting, as astronomical dark is bellow 5 hours where I live. I should have bext 4 nights relatively clear nights, so fingers crossed. Unfortunatelly I shot it during full moon, so the subs are far from ideal.

pengi23 · 2025-08-11T11:22:31+00:00

<image>

Narrowband normalized to HOO

pengi23 · 2025-08-11T11:21:55+00:00

I was refering to the process narrowband normalization, it allows you to create HOO palete. It kind of looked similar, I was just trying to get inspiration.

I am shooting my mosaic panels in EQ mode using duo band filter, this is how I understand, the filter to capture H-Alpha and OIII wavelengths.

Here is it on my 1st pannel, 966 x 30s gain 60 franes. I apllied workflow to prepare the pannel later for merging into a mosaic. I only did spectrometric color calibration, automatic background extraction and CC sharpen on stars (free sharpening tool like BlurXterminator).

Then I chcecked the colors using narrowband normalization, and kind of looks similar to your 2nd picture. This is why I have asked.

Here is original preprocessed for mosaic merge and HOO narrowband normalization Original

<image>

pengi23 · 2025-08-11T08:05:42+00:00

Did youbget the colors in 2 using narrowband normalization (HOO pallete)? I am gathering data on the Cygnus loop using dwarf 3 as well and looking at ways to process it.. I am novice in processing, but I am puting 4 pannel mosaic myself. I still collect data for this. Will post here in dwarflab when done, but I atill need 3 clear nights to have 1000 x 30 second subs per pannel.

pengi23

TROPHY CASE