eshy76

Hey @knobby I've got a HEM27EC, but haven't used it for a couple of months due to weather. Initial impressions were positive but I just wanted to ask whether meridian flips work consistently for you? On mine, the flip happens but the guiding goes nuts afterwards...I must have the wrong PHD2 setting selected or something. I'm sure the meridian flip would behave similarly for EC and non-EC versions which is why I ask. Looks like three clear nights coming up for me, but with a full moon stomping all over the Pleaides/Orion part of the sky, not sure which narrowband targets to shoot!

Hi everyone, This year's Soul was captured using two rigs simultaneously (two strain wave mounts no less, the RST135 and HEM27EC), one using an OSC camera and one using narrowband filters. I then decided to combine the narrowband data with that I captured in previous years. This year's data added about 13 hours to the overall 26 hour integration time...in one-and-a-bit nights! I then decided to try to process the NB in as "natural" a palette as I could muster, with the ratios being: R: 67%*Ha + 33%*SII G: OIII B: OIII Finally I added back the RGB stars from the OSC capture. Phew! Full details here Thank you for looking!

Hello, I have an image that i added 13 hours of data captured in September 2022 to data acquired in previous years. The new data amounted to 50% of the overall integration time. Would that be permissible?

Congrats to Emil and the others on the podium! Very chuffed to have got a mention for my image of a much longed-for target!

What do we have here then? Open box for a few hundred quid off...logical that the weather is pants for the foreseeable! If the weather ever clears up hope to get this up and running soon and will compare to my Rainbow Astro RST-135.

I was lucky enough to go to Mauritius for a couple of weeks this month for a family holiday and took advantage of a clear night! I dashed away from my family after dinner and set up on the Bortle 4 beach at my hotel in Pointe Aux Piments for a couple of hours, gunning for one of my most lusted after targets, the Rho Ophiuchi cloud complex. I know the challenge refers to star trackers, but I chose to bring my tiny Rainbow Astro RST-135 mount which only weighs 3.3kg, so I'm not sure if that is allowed for this! Imaged on August 16th with an Askar FMA180 and ZWO ASI2600 MC Pro. 84 x 60 second exposures at 0 gain. Here is an image of the setup in situ for full disclosure!

Very nice image! Thanks for sharing! Yes it's always worth trying despite conventional wisdom being against it...I had another night's data on Rho on a full moon night, with the moon very close to Antares...I went for it anyway, partly to dry run the setup (which definitely helped on the beach a week later), but the subs were definitely washed out! In general, for me I notice that the quality of my images degrades sharply below 25 degrees at home in Sutton, Surrey. Hmm...maybe I'll pop my own image into that holiday challenge thread too!

Thank you... it's one of those to target when you are in the Southern Hemisphere, though with a DEC of -24, this is probably very possible from anything around 20° N. The focal length I used here is 180mm, but something like a Samyang 135mm lens would also be great for this, so a light travel setup with a modded DSLR and tracker could definitely work too!

Thank you!

Thank you very much Bryan! It is definitely great for all the planning to result in a nice image!

Thank you! I'm chuffed with the result...I could've maybe got a few more hours integration, but I couldn't keep dashing off from my family after dinner! (Night was from 7pm there and Rho went from Zenith to below the horizon by about 11.30pm)

Hi - thank you! Mauritius is actually mostly Bortle 5 in the built up areas, but around the coast and the forest regions a bit better! But yes the population (including tourists) vs. land equation is the key factor.

Here is the kit on the beach! In hindsight I should have prepared all the cabling ahead of time instead of connecting everything up in situ, though that went smoothly albeit with cable spaghetti...I used a bog standard carbon fibre tripod which was okay...but I can see from the photo I left the central column extended which was not meant to happen, but hey I was in the dark! The sea is about 5 metres away in the darkness. I saw several shooting stars during the evening which was amazing, while the chitter of fruit bats added something unique to the experience!

Hi everyone, It's been a while from me, but the astrophotography flame is still burning brightly within me! A trip to Mauritius this month was an opportunity to catch up with family and friends after several years, and also a chance to put a travel rig together for some darker skies! After flirting with bringing a modified DSLR and Skyguider Pro, polar alignment considerations (with no guarantee of visibility of the Southern pole at the 20° latitude) convinced me I needed a computer and NINA for its TPPA which works regardless of pole visibility. Once I took that decision, there was no reason not to bring my 3.3kg Rainbow Astro RST-135 mount, apart from my own nervousness at carrying such expensive kit with me...once I got over that, the DSLR was replaced with the ASI2600MC Pro, to be paired with the Askar FMA180 lens to target Rho Ophiuchi. Power was the next concern, which I solved by bringing two close to 100Wh (so hand baggage compliant) lithium ion batteries. Everything including guidescope and cam fit inside my hand luggage, weighing about 15kg. Anyway, to cut to the end, I got lucky with the weather one night while staying at a hotel and spent a couple of hours on the beach...imaging on the sand was a new challenge, with my tripod almost certainly not level, but I got guiding consistently below 1" RMS, which was fine for my pixel scale. I only got 84 minutes of data, but I hope that imaging at a Bortle 4 site Vs my usual Bortle 7 skies made up for that. Here is the end product - I love this part of the sky and whereas it doesn't get above the rooftops at home, in Mauritius it passed through the Zenith! I'll also post an image of the setup on site in the next post - thanks for looking! Full details here

Yes I have my eye firmly on the EC version for this reason. I also have and love the RST-135 (non E) for my refractors, but it is not quite good enough to guide my 8" EDGEHD....the 0.5 second guide exposures needed for optimal performance all but rule out an OAG for the EDGE, but the feedback from the RST-135E suggests the encoder-tamed PE allows for 2-3 second guide exposures which brings the OAG back into the equation. If the HEM27EC does similar at a significantly lower price than that mount, as you say, it could be a game changer for longer focal length imaging.

Thank you very much!

Hello! This is my entry of the Alnitak region: IC434, the Horsehead Nebula and the Flame Nebula. Taken over 4 nights in January 2022, the 4th, 5th, 13th and 14th. Taken from my garden in Sutton, Greater London (Bortle 7) using the ZWO ASI2600MC Pro camera, Rainbow Astro RST-135 mount and William Optics FLT91 refractor. Captured using NINA and Voyager, stacked in APP and post-processed in PixInsight. Total integration time of 9 hours 8 minutes, 137x120s using IDAS NBZ dual narrowband filter and RGB subs split between 235x30s and 157x60s.

Bravo, breathtaking image!

No problem - I started by using Gain 100 at all times, which definitely works really well...I just wanted to experiment with pushing up the dynamic range up for non-narrowband captures...to be honest in this image, the reds really stood out from the NBZ filter relative to the RGB data....so I'm not sure if this approach made a lot of difference here.

Thank you! So I've been fiddling with my ASI2600MC Pro camera for a few months and trying to lock down optimal exposure times...I've been looking at the methodology that Robin Glover (Sharpcap creator) uses - I had some calculations as my base game plan and adjusted from there, mainly for practicality. The logic was (some trial and error in here): 1. I wanted both RGB and Ha data for this image 2. My very first night, I was using no filters, just straight RGB, and the suggested optimal exposure was something like 7 seconds at Gain 0! I rounded that up to 30 second exposures so that it would be manageable for my computer in terms of number of subs for stacking! 3. After an initial stack of night 1's data, I could see the light pollution was causing havoc, so on night 2 I used a broadband light pollution filter - the IDAS P2....while still broadband, this filter would lead to darker subs, so I decided to increase the sub length to 60 seconds to compensate (and ease the processing burden further on my computer). 4. On the third and forth nights, I used the narrowband filter (the NBZ) for Ha/OIII, so a longer exposure time + higher gain were needed...120 seconds seemed to be close to optimal for my light polluted skies, using the default gain of 100 and based on my calculations beforehand. Hope that makes sense. This camera's noise is so low, that operating at Gain 0 (higher dynamic range) is no problem (and probably beneficial) from what I can see.

Hi everyone - it feels like an age....probably because it has been, thanks to the clouds...they finally gave way in January, and I decided to shoot for a target I last imaged in early 2019. It is a classic, well-imaged target of course, but what a target! IC434, the Horsehead and the Flame just seem to make the heart soar when they pop out of the screen after stacking! Even Alnitak was a welcome sight, as it didn't completely dominate the image this time around! First lights galore in this image, with a new refractor (William Optics FLT91), a new mini-PC (MeLe Quieter2) and the IDAS NBZ filter put through their paces (I bought these in December, so the December cloud out is entirely my fault!). As you can imagine, there was a lot of jiggery-pokery going on adjusting everything and more than a few excursions into the icy garden in the middle of the night to figure out why the guiding had gone to pot, etc. Also a rather painful processing run, I decided to split the Ha and OIII data from the NBZ capture and blend them with the RGB channels from the OSC data I also captured - I used a 70% Ha weighting within the Red channel and a 30% weighting of OIII within the Green channel. My usual StarNet approach to doing this floundered, so I masked the stars in each NB channel before combining, which seemed to come out okay. But of course all those quibbles are forgotten when the image is finished! Total integration time 9 hours 8 minutes. Main equipment William Optics FLT91 Triplet, Rainbow Astro RST-135, ZWO ASI2600MC Pro, IDAS NBZ. Full details on Astrobin here Thanks for looking!

Well I personally was lucky when upgrading - the 3/8" screw connection of the RST-135 fit my iOptron CEM25P 1.5" tripod (and its minipier) perfectly, so I'm using that! It's all about ensuring the tripod does not topple, which is why one could choose to use a counterweight even if it does not necessarily improve guiding. I admit to being nervous about using a carbon fibre photo tripod with my setup for this reason, but lots seem to successfully.

Well the other mount I was considering upgrading to was the CEM70, which would have been 17kg without counterweights…I can tell you that my 3kg RST-135 has been used on many more marginal nights than would have been the case with a much heavier mount, for someone like me who has to set up and tear down the mount each imaging night. So yes, there is a practical benefit, added to the lowered set up time through not having to balance the OTA. And on your other point, with my 73mm aperture refractor (3kg) + imaging gear…it is actually possible to carry the fully assembled rig in and out of the house, which is what I do for even speedier setup! Granted that would not be possible with a heavier scope, but for a widefield refractor, eminently possible. The benefit of this mount is its portability and lightness while still packing a punch payload-wise and without compromising performance when guiding. If you have a home obsy/pier, intend to image at focal lengths of above 800-1000mm or value tracking accuracy above everything else, then this type of mount is not for you. If you want a more-than-capable portable travel mount, or need to set up each time you observe/image and dread having to lug heavy gear out, harmonic drive mounts can be a great option.

Harmonic drives are heaven for portable widefield imaging, or anything below 800mm focal length. They are strong mounts with zero backlash, no balancing of OTA needed, no counterweight needed except if you’re worried your tripod will topple, a gentle PE curve that can be guided out to a consistent 0.5-1 arc seconds. And all this in a mount weighing a backache killing 5kg (my RST-135 is actually 3kg!). The mounts can easily cope with Edge HD scopes weight wise, but the need to use something like 0.5 second guide exposures make it hard to use an OAG for guiding. I think £2k is quite compelling for the above if the quality is good.

Thank you!