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From a tracker to a permanent observatory in a village: advice needed


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Hi! My name is Alejandro but you will find me as @aleixandrus in the web. I'm a landscape/nightscape photographer based in Spain. I've checked this forum many times in the past but I never registered. Well, now it's time for that :)

I'm about to move to a new house with garden in mid 2022 so I plan to go 'full' into astrophotography. My mid term goal is to build a small observatory/shed to control all equipment from home so I need a bit of advice to avoid unnecessary mistakes.

1. Location: It is a very small town with Bortle 4 skies (SQM 20.70 - World Atlas 2015 and Radiance 14.41 - VIRRS 2021) according to the Light Pollution Map. The house is in the middle of the town, with some streetlights around. Free horizon is ~25º except to the North (~35º) but I need to check this better as some trees/streetlights may be in the FoV once I place the mount. There is a 100k city towards the West at 10km straight line. The area is quite horrible in terms of clear skies. Average yearly data: 140 days with precipitation (plus cloudy days), 75% (summer) to 85% (winter) relative humidity, 4-25ºC minimum/maximum temperatures.

2. Current equipment: Sky-Watcher Star Adventurer + Sony a7III (unmodded) + some 16mm to 200mm f2.8 camera lenses. I had the Samyang 135mm f2 and a Newton 900/114 EQ1 fully manual in the past.

3. Knowledge: I love shooting nightscape pics of the Milky Way and wide field astrophoto with that tracker. I know the rudiments of astrophotography and I've used a GoTo mount a few times. I use DeepSkyStacker and Photoshop without much trouble. I also started using PixInsight but I'm a completely newbie right now.

4. Hopes/Objectives: I pursue astrophotography only, not visual. Well, I love seeing Saturn so I probably should rethink this :) As the location is not ideal, I plan going narrowband with a monochrome camera as I'm not sure if LRGB is feasible. The setup will be permanent, I'm not planning moving to a darker site at all. I like nebulae more than galaxies but, to be fair, I'm not sure what I like right now.

5. Desired equipment: Sky-Watcher EQ6-R + Esprit 100 + C8 + ASI1600MM + LRGB/HSO filters + guiding (or similar equipment). I plan build a permanent pier as soon as I had checked the optional location in the garden. A shed without warm room will come later.

6. Questions:

- How 'bad' is the location? How much I should be worried about direct streetlights? Is LRGB feasible under that sky conditions? What about cloudy/rainy days? Going mono makes sense or should I go OSC?

- I know and I agree that the 'mount comes first' but the desired equipment is quite expensive so I will need an intermediate step. Hopefully, this will allow me to acquire experience. Which route should I take? Stick with the star tracker and buying a wide field refractor in the 200-300mm range, a dedicated camera and narrowband filters with/without guiding? Go for the GoTo mount and stick with my unmodded DSLR plus lenses and CLS filter with no guiding? Get a lower specs -cheaper- equipment but buy it all at a time?

- This is a hobby and getting fun is important so I don't want to 'burn' myself trying to make work equipment off limits. Both the star tracker router with >200mm scope or the unmmoded camera under light polluted skies scares me so I'm open to other proposals. 2nd hand is an option but I need to establish a route before. Also, I don't want to enter in the buy-sell cycle, I prefer to buy one but buy right.

For those who reached this point... thanks! Any comment will be very valuable :)

 

PS: I posted this message in the 'Discussions - Scopes / Whole setups' as I feel it fits better but feel free to move to the 'Beginners' section if it makes sense.

 

Edited by aleixandrus
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I'm quite certain your decision to go mono-narrowband is the right one given the nearby lighting and the EQ6 is a good mount for imaging at moderate resolution.

While there are, of course, small narrowband targets like planetary nebulae, I'd suggest that most are extended and tend to get bigger the deeper you go!  So I'd prefer a short focal length over a long with a chip as large as the optics will support. Another thing about NB filters is that they hold down the star sizes. This means that premium optics and larger apertures (which hold down star sizes in LRGB imaging) are less important for NB imagers. In other words, small widefield optics do better in NB than they do in LRGB. These would be my two arguments in favour of a widefield narrowband rig and lead nicely into a possibility you might not have considered - the Samyang 135 camera lens. It has its own thread on SGL and has become a modern legend.

Olly

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Thanks for your comment, Olly, I appreciate that.

I suppose narrowband is the safer choice but here in north Spain weather is a pain so not sure about going for image quality (mono) or image quantity (OSC). Hard decision. I have no decided at all which OTA/camera combination I will choose. Right now, is more a "what comes first" as I (probably) can't afford the whole setup ta a time. Update tracker? Update camera? Update OTA? Probably update the mount is the way to go as is the basis of any astro setup but I love to see your thoughts.

By the way, I had the Samyang 135, love it except for a very specific issue with concentric rings when I stretch the image. I'm not completely sure if due to bad calibration, in-camera RAW processing (love my Sony for landscape/nightscape, not so for DSO imaging) or editing, but it was a pain. I sell it hoping buying the Canon mount version to ease adapting a dedicated camera. I had no opportunity yet 😔 Right now I directly plan save that money to buy a proper OTA.

When you say "While there are, of course, small narrowband targets like planetary nebulae, I'd suggest that most are extended and tend to get bigger the deeper you go!", what do you mean with "tend to get bigger the deeper you go"?

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  • 4 months later...

Well, this post didn't drove much attention but, for those who are curious, let me add some updated info.

The EQ6-R route will have to wait, prices are crazy and there are many stock issues. In addition, I've found an opportunity to buy some used gear in good condition at good price. I made the decision and now my (untested) setup is:

  • New: ZWO ASI183MM Pro + Samyang 135mm f2 modded with M48 thread and custom rings/dovetail + ZWO EAF + ZWO EFWmini + ZWO LRGB 1.25" filters + Williams Optics Wedge
  • Existing: Star Adventurer (the original one) + photo tripod

I think it may be a decent setup to start with. I'll need narrowband filters, guiding and think how to power and control everything (Asiair?) but I hope this will allow me to acquire experience, test my backyard conditions and figure out and plan future upgrades (EQ6-R, I'm still watching you). I'll miss goto but... well, I think this is a good starting point. Fingers crossed!

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Bortle 4 is fine for LRGB.  I travel to Bortle 4 regularly from Bortle 8 so l can do LRGB imaging.  However this might depend on how bad the nearby lights are.   If tou can manahe to shield your rig this will help.   
 

l have to do narrowband at home and some targets ate better in narrowband anyway.  Just pick your targets.  A good equatorial tracking mount capable of guiding and a cooled camera will make a lit if difference. 
 

Carole

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On 08/01/2022 at 14:48, aleixandrus said:

 

When you say "While there are, of course, small narrowband targets like planetary nebulae, I'd suggest

that most are extended and tend to get bigger the deeper you go!", what do you mean with "tend to get bigger the deeper you go"?

Sorry, I didn't see this question back when you asked it. What I meant was that many emission nebulae are surrounded by faint extensions which are often overlooked if you don't have enough data. A classic case, for us, was the pair of emission nebulae near Gamma Cass, IC 59 and IC 53.  When Tom O'Donoghue and I decided to do a very long, deep run on them in Ha we suspected that they were acutally just the bright parts of a larger structure so we did a 3 panel mosaic. It turns out that the two nebulae are really one and go all the way down to the Pacman nebula.

Breaking Wave and Pacamn reprocessed web small.jpg

Olly

Edited by ollypenrice
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2 hours ago, aleixandrus said:

I think it may be a decent setup to start with.

You'll enjoy the 183mm, it's what I use. If you add in an azgti (you can diy a counterweight and bar), asiair and a small guidescope plus something like a 120mm you'll have a full goto autoguiding setup. After that you'll want to add in a telescope... then a new mount... then...

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3 hours ago, carastro said:

Bortle 4 is fine for LRGB.  I travel to Bortle 4 regularly from Bortle 8 so l can do LRGB imaging.  However this might depend on how bad the nearby lights are.   If tou can manahe to shield your rig this will help.   
 

l have to do narrowband at home and some targets ate better in narrowband anyway.  Just pick your targets.  A good equatorial tracking mount capable of guiding and a cooled camera will make a lit if difference. 
 

Carole

My concerns are not only light pollution but direct illumination due to street lights... That's why I went mono, for doing narrowband. The LRGB filters were cheap as the seller made me a bundle so, for 50€ extra, I said I should try them.

1 hour ago, Elp said:

You'll enjoy the 183mm, it's what I use. If you add in an azgti (you can diy a counterweight and bar), asiair and a small guidescope plus something like a 120mm you'll have a full goto autoguiding setup. After that you'll want to add in a telescope... then a new mount... then...

Yeah, I know I'll eventually need a 'full' mount but for now I'll try my Star Adventurer. I'm considering the CEM26/HEQ5 at minimum but time will say. I need setting up many things before that! :)

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By all means, I would advise try with what you have and see what results you can achieve as my recommendation is added cost. I too had a SA and got frustrated trying to find targets, the azgti solved this completely, and I still use it more than my gem.

Edited by Elp
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For starters it would be good ideea to stick to refractors, low to mid focal lengths. I made the mistake of starting with a SCT and I've spend 2 years mostly tinkering than actual imaging. Last year I have switched to a refractor and I actually started enjoying the hobby. From your location you can do LRGB and narrow band with no problem

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Don’t be too concerned about the streetlights. I image LRGB from a Bortle 5/6 location with some prominent LED streetlights to my Southern horizon, but thanks to modern cameras and Light Pollution removal software, I can still get reasonable results.

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