aleixandrus

Hi! Resuming my 'old' question, I think I'll go with the normal 6.5nm Baader narrowband 31mm filters. I was reading the "Narrowband Filters on Astronomical Telescopes" white paper from Baader and I concluded that, as the 'normal' narrowband filters are rated for >f3.4, they should be fine (although not ideal) for f2.8, the f-ratio I plan to use. My future scope will be slower than f4 for sure (some type of 400-600mm f4-f6 APO, probably) so I can use those filters. Going 31mm will be future proof for a ASI294MM or similar (I don't plan to increase sensor size). I live in a bortle 4-5 area although in the middle of the town. I think it doesn't make sense go 3.5nm filters. I also considered the Astronomik ones with MFR coating, as they claim to work up to f3 (12nm) and up to f4 (6nm). The Astronomik MaxFR filters claim to work f1.4-f8 (12nm) and f2-f8 (6nm). However, they are almost 2 times more expensive than the Baaders and they don't seem to be twice as good so... Being poor is a doom 🥲 What do you think? May I regret this decision? PS: These links are available in previous posts but worth posting them again: Baader filters and preshift for fast systems, including whitepaper: https://www.baader-planetarium.com/en/blog/preshift-and-further-information-concerning-baader-cmos-filters/ Baader narrowband filter selector based on current equipment: https://www.baader-planetarium.com/en/baader-narrowband-highspeed-filter-selector/ PS2: A combination of bad weather, busy calendar, mechanical issues trying to get optimal backfocus and the inevitable learning curve including NINA forced me to take me this hobby slowly 😅

31mm then! :) Cost is not very different. Why did you switched brand? I'm between Baader and Astronomik filters...

Thanks a lot! I think I'll go for 6-7nm filters, seems the best compromise. In addition, O3 suffers more from light pollution so the more restrictive the better (please, correct me otherwise). If those Astronomik work well for fast systems, I think they may perform better than the Baader. I'll have to check this carefully. Any comment about filter size? I know 1.25" are enough for my ASI183 and I don't plan to go further in the mid term (maybe a ASI294 in the long run, but even 1.25" seems to be acceptable). I have the ZWO EFWmini filter wheel and the documentation says: The distance between the filter and sensor is around 10mm when you connect it to ASI1600. So 1.25″ filters won’t have vignetting up to F5 focal ratio scope and 31mm filter won’t have vignetting up to F2 lens I suppose I should go with 31mm unmounted to avoid issues...

Hi! Well, it took a while but I managed to read all the 42 previous pages of this mega-thread :) There is a lot of very valuable information. Most of the notes I took were related to the mechanical assembly as it was the first problem I had to tackle. Now, I'm checking for narrowband filters. What I found is many of you just simply use 'conventional' filters but others use 'CMOS optimized' filters or even 'High Speed optimized' filters for f2-f4 scopes (such as the Baader High Speed 6.5nm Narrow Band Filter - CMOS Optimised). No consensus here. I have an ASI183MM Pro and I don't plan to go crazy with 3nm filters but 6.5nm or even 12nm wide. I guess the wider the band is the less important redshift is. I also plan to add other scope in the future but as it will be slower (it's hard to go faster than f2!), I don't want to buy an additional filter set. How critical is redshift for this lens? Should I go for 'high speed' filters or may I go with 'conventional' ~12nm or ~7nm filters? In your experience, is there any specific filter or brand I should run away from? I want to buy once, but buy well. Thanks a lot!

Thanks for your input, very valuable. I think my comments are in line with yours but I don't want to 'steal' this thread with more questions so, if you find my questions too intrusive, please, let me know and I'll open a new one (or if any admin considers split this conversation, go ahead). Yesterday night I set all the equipment outside to do some (very poor) tests. Many things went wrong, as expected, but that was the goal, find out what's wrong. This includes power and cable management, drew protection, better wifi coverage and test software better (I installed NINA on the field 🙈🤣). Regarding the main point of this thread, I set the following backspace: ASI183 (6.5mm) + EFWmini (20mm) + 16.5mm ZWO adapter + (0.1+0.2+0.2+0.5 spacers) = 44mm, which is most of you pointed out. I tested this without filters and with the ZWO 1.25" L filter, which I think is 1.9mm thick, so I should need ~44.6mm total. I keep the 44mm distance as I didn't have more spacers... I focused using the EAF 12V, manually, until the stars on the laptop screen seemed 'right'. I used ASI Studio just for simplicity. I've attached a preview of two single shoots: 120s at f2 and f4. No calibration frames nor stacking. What I found is a a strong vignette and worse star shapes @f2 compared to @f4. Brighter stars seems bloated but there was a lot of dew and I didn't use a lens warmer, so not sure if was due to filters quality the automatic STF in PixInsight, focus issues or anything else. Star trailing seems ok to me spite of being 120s with no guiding. Using no filter but keeping the same focus, stars were *completely* out of focus, but I can achieve focus after refocusing. I think 44mm backspace works for me but... What's your impressions? What additional test should I perform? Should I meassure star diameter for better confirmation? What to improve? Thanks a lot star-test.zip

Wow, you have some powerful streetlamps nearby! Can't you shield them somehow? Impressive image, by the way, it encourages me to try even harder

Yeah, I already have considered doing that... but once I have all setup working Oh, thanks a lot! Huge help. My math said that but it is good to know it is right! Let me check all your info carefully, I may have some issues with that extra 1mm I need to check. By the way, I'm aware of the mega-thread about the Sammy but it is so large it takes me a while to read and extract the most important info. But I'm on the way

Hi @groberts! Have you found a valid solution for your setup? I'm exactly in the same situation so any information would be welcome. My equipment is: ASI183 (6.5mm) + EFWmini (20mm) + Samyang 135mm f2 with Canon mount replaced by M48 adapter

Yeah, finding targets with the Star Adventurer may be... tricky. Specially with narrowband filters. I plan using plate solving from day one so hope it eases this task a bit. But I appreciate you comment, I know you're right

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. 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! :)

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!

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"?

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.