Pompey Monkey

I'm not 100% convinced that those pictures were even taken with that device. All it says on the Vaonis site is 150 mm scope, integration time, and IMX 455 sensor...

I can't think why not. I've been thinking about re-purposing (or even multi-purposing) an e-bike battery for the same reason. 48 V 840 Wh should keep an HEQ5, TEC cameras, dew-heaters, and all the other bits going for a whole night. At around £300, they are not the cheapest, but don't half pack a punch!

There's no harm in getting focus on a bright star and then slewing to your target. However, you should ideally re-focus when on target in case anything in the optical train shifts slighty with the scope in a different attitude. Especially if you are using a reflector or catadioptric ota.

If you are polar aligned but your gotos are out out in elevation, this suggests that the star alignment is incorrect. Are you definitely syncing to the correct stars when you do your alignment?

I also forgot to say that the 3 nm Ha also blocks a lot more of the light pollution from the Moon, meaning that you can image for a larger part of the month, whatever Bortle skies you have! The OIII and SII filters are not so good at blocking the moonlight.

I'd advise based on your light pollution conditions: If you work from a good dark site, then the 6.5 nm versions will do you fine. However, if you are suburban/city based, then the 3.5 nm will reduce the effects of light pollution a lot more, improving contrast and making your processing much easier. I'm in a Bortle 7 (6 on an exceptional night) location, and when I changed to 3 nm from 7 nm nb filters, the difference was very apparent. Having said all that, nb imaging does require long exposures (10 minutes+) and you need to be sure that your EQ5 mount can consistently do that, or you will be chucking out lots of subs...

Even if I do get stung for VAT, at least there is no import tariff https://www.trade-tariff.service.gov.uk/commodities/8525801900#import

Hmmm, I was under the impression that Aliexpress was bound to include the VAT on sales to the UK by government agreement. https://www.moneysavingexpert.com/shopping/buy-from-china-aliexpress/

My order has been placed. Looks like there is only one left for now: This price includes UK VAT!

Now I'm really confused! Here: https://www.omegafilters.com/resources/glossary#:~:text=The width of the band,and shorter than the passband. it says that HBW and FWHM are the same thing.... Maybe I should get me coat....

Interesting. I've had my eye on a set of 36 mm unmounted filters from the UNB range but now I'm not so sure. Baader states a HBWs of 3.5 nm (H-alpha) / 4 nm (O-III / S-II): https://www.baader-planetarium.co.uk/shop/baader-cmos-optimised-h-alpha-o-iii-s-ii-3-5nm-4nm-ultra-narrowband-filterset/ I can't find any more details than this. On the other hand, Chroma specifies a FWHM (with measurements) of 3 nm: https://www.chroma.com/products/parts/h-alpha-3nm-bandpass#tabs-0-main-2 and https://www.chroma.com/knowledge-resources/about-fluorescence/fluorescence-applications/glossary This implies that the passband of the Chromas is only half that of the Baaders. Having a job that requires a good appreciation of systems engineering, I'm always on the lookout for specification discrepancies like this. Are we being mis-sold/misled, or is it that the marketeer for Baader just doesn't understand the difference between FWHM and HBW? Does anyone know the truth?

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This may not be the answer you were looking for, but for the price of a new EQ3 Pro, you could pick up a second-hand HEQ5 with Go-to. This has twice the capacity of the EQ3 and will give you much more future-proofing. Edit - Second-hand prices are stupid at the moment due to shortages of new kit.

That is amazing. The PN is approximately the same angular diameter as Jupiter!!! Edit to post the Astrometry result: https://nova.astrometry.net/user_images/4450663#original

I tried to use AutoPEC with my AZEQ6GT a few years back. It failed miserably, basically because there is no worm position information coming from the mount. The encoders only "tell" ASCOM where the telescope is pointing, not what's happening to the worm. You are on a hiding to nothing and, as other have said, the guiding is OK without the AutoPEC.

Whoops! I got the camera mixed up. I was thinking of an ASI6200, and a set of 2" Chroma filters... On the other hand, I already have a set of 36mm Chroma nb filters.... hmmm

It's a stunning image. I cannot say more than that about it! Now I just need to find £7k+ to buy the mono version of the camera and the required 2" filter to stick on the Tak that's sitting in the bedroom that's waiting for the Covid to be under control... I have no idea which will happen first (unless I put off the double glazing for another year) 🤣🤣

This is exactly what they do in La Palma, and the effect is a bit surreal: All the streetlights are shaded to direct the light down (by law), so if you are near, or in a village, it is quite possible to get dazzled when in line of sight to one. However, turn a corner into the shade and it's dark enough for you not to see where you are. The sky is absolutely incredible, so directing the light downwards actually really improves things.

This looks like an excellent start. With all that thought and planning, it's bound to go wrong somewhere! (joke) The only thing I can see that may cause you issues is the mounting of the guide-scope and computer to the stand-off plate. This could cause you an issue with differential flexure between the guide and main OTAs, especially as you are imaging at a little over 1" per pixel. On the other hand, it might work just fine. If you do have this problem, maybe beef up that aluminium plate a bit. Double the thickness feels about right to me. Basically though, you look good to go

What camera are you using? 60 (or 45) 60 second subs won't get you a lot of nebulosity at all with a DSLR. If you have poor data to start with, then you are already facing an uphill battle.

That thing is really, really, faint. Good work.

Spot-on, apart from the Read-noise. This is a constant for all exposures relating to the electronic process of converting the charges on the sensor into an output signal. This is also known as Bias. The noise component measured in electrons per pixel, per second, is the accumulated charge on the sensor (hence "per second") for each exposure. his is known as Dark current. Dark current is a lot lower in the newer CMOS cameras compared to CCD. There are other differences, but That is for someone more knowledgeable than me to answer!

What @ollypenrice said: dithering will really help you with the noise.

Most excellent, dude!