bomberbaz

Ok so here in lies part of the issue with your scope. F10 / 25mm ( your eyepiece) is giving you an exit pupil of 2.5mm, if it was F5 you would have 5mm. The former gives you an area coverage of your retina of 4.9mm sq, the latter 19.6mm sq. So you get 4 times the level of retinal neurons activated by the faster F5 ratio meaning dimmer objects are brighter from your perspective. To get around this small exit pupil you could A, get a larger focal length eyepiece such as a 40mm plossl, which is the largest available 1.25" eyepiece to you and would give you a 4mm exit pupil / 12.5mm sq retinal covereage and this would make a significant difference to dimmer objects. Option B you could get a UHC filter (get a decent one if you take this option) as this would isolate the OIII & HB lines in the nebula and make it stand out more against the now darkened night sky. However the effectivness of a UHC is variable but an exit pupil of 3-4mm is generally optimal on diffuse emmision nebula. Another option is to get a 0.5 reducer as this effectively gives you an F5 scope which as we have seen increases your exit pupil and is also the cheapest option I believe (£19 with flo). It might produce some aberrations to the view as a result but you would have a greater chance to see the eagle easier than at F10. The best option imho is a combination of UHC and either reducer or longer focal length eyepiece.

what scope were you using to observe the nebula? The focal ratio/length can have a big bearing on nebula, especially in smaller scopes. As mentioned above you also need good transparency for viewing nebula, and a larger exit pupil is preferred especially on more diffuse and dim objects. Can't understand what the guy was on about telling you UHC filters don't really help. They provide a huge difference on very many objects, see here : Filter Performance The crab without a filter is little more than a fuzzy blob. With one you will see more structure to a point but the best all round thing for nebula viewing is dark skies (with a good filter).

Just so you know, I have a 183MC pro and I use it to good effect with the 72ED.

Depends which P-DS scope you use but a pixel size of 3.75 should be ok with either option or you could bin a smaller one. You didn't state cooled or not although cooled is preferred for deep sky. The ZWO 533MC pro should be a suitable candidate, retail new at 859 with flo so a 2nd hand one should be available under 600. The other option would be the 183MC pro but with the 200p-ds it would need binning. The 294MC pro is another that 2nd hand might come in at your budget but at 1060 new that's a bit of an ask. EDIT. @Elp beat me to it alkthough I didn't know about the 294 colour pattern issue so I personally would scratch that off my list.

As michael says above a panoptic would give you max FOV but at a price, for roughly half the price the stellalyra UFF gives you almost the same at just 3 degree reduced afov StellaLyra 24mm Ultra Flat Field 1.25" Eyepiece | First Light Optics On the planetary side I would go zoom all day every day, much more flexibility on the day for conditions and still gives you near x180 Hyperflex 7.2mm-21.5mm Eyepiece | First Light Optics

Skywatcher Quattro 150P F4: 5.7kg. Significant difference and when I throw it onto a HEM15, it won't need a CW, hence the consideration

weight wise it's heavier than what I am considering but thanks for the pointer

Ok so my question has been asked before of that I have no doubt, the question differences of using a frac or newt for imaging. I currently use a SW 72ED which I have to say is a lovely bit of kit and gives some pretty good results but I have been looking at other options for reasons I shall keep to myself. So considering this 150/F4 newt as another option StellaLyra 6" f/4 M-LRN Newtonian Reflector with 2" Dual-Speed Focuser | First Light Optics Just wondered if anyone has one and can feedback on performance, does it accept a auto focuser. also what difference I might expect in return in performance terms giving consideration to all aspects IE colour correction, integration speed, flat field/coma etc I can ask FLO direct most of these questions but I always value my fellow astronomers thoughts. cheers steve

4 hours data, all from my garden with accompanying hotel car park lighting. So restricted to 2 minute exposures, 72ED, 183 MC Pro and askar dual band filter. Quick word on the DB filter, a huge step up from the previously used zwo version. Sharper and smaller stars and notable improvement in contrast. If I can get away from my garden I would like to add another hours data from a dark site but overall it's not too bad from what data I do have.

celestron astromaster 130eq. Purchased in the hope I could do some tinkering to make a useable lightweight imaging ota. Proved a fruitless chase of ambitious modifications that celestron have made nigh impossible due to use of moulded fittings.

One of the better science sites in my opinion. Juice, why is it taking so long!

I was particularly pleased with the edges looking sharper of the actual nebula Lee, py-astro/sharpen/smart sharpen tool in gimp (used sparingly)

I found some old data I had forgotten about so I thought I would have a go at re-working it using techniques I have learnt/honed since the first process. I am still far from an expert and can only dream of doing as good as some I see on here but I am happy with the result. I seem to remember this was about 4 or 5 hours worth but all done from my cozy (but light polluted) back garden. Top one original, bottom re-work.

I have recently started out in spectroscopy and these are fascinating objects to get data from also WR stars respond particularly well to camera's for obtaining spectra. At mag 8.05 it should be a great candidate. As for your image, I struggle for adjectives that give it enough praise, it is stunningly beautiful and would give hubble a run for it's money. 💕it.

oh but you can have hours of "fun" collimating and I am entirely with you Mandy. I had a similar journey of fun with a Heritage 130p using first the OCAL collimator to get the secondary beautifully collimated, I was so happy at doing what I thought was a model of collimation. Upon removing my coloured card blanking sheet, the primary was a country mile off. So I put in my new and perfectly collimated baader laser and in a few minutes the whole system looked perfectly aligned. Until I popped the OCAL back in which showed my secondary was now out! HOWEVER, a laser recheck showed a superb alignment so we are full circle and I decided to leave well alone! Steve.

No campbell's H star rob? ignore me, I have seen it

I think this is what your looking for! Dual-Axis D.C. Motor Drives for EQ-5 | First Light Optics

Great filter and seems you adopt the same approach as me, get the best. My largest exit pupil from eyepiece is 5.6mm, I won't go any higher than that. Your heritage should be ok with a 25mm plossl or similar. I did some comparisons a year or so back using eyepiece sizes up and down from a 5mm exit pupil, even small differences make a fairly significant change in surface area. Smaller didn't help, larger was better but 5mm seemed to be a safe bet to recommend as optimum size exit pupil. A good dso to test this out on with your scopes, assuming you see it at all is the crescent. Let us know how you get on won't you. Steve

Rob, what brand of HB filter did you get and do you have a 40mm plossl? The 40mm should give you a stronger response. Also I notice you have the heritage 130, now an interesting comparison there would be that shooting off against the 4" apo with the HB filter.

Yes I really must try varying my nebula observing methods a little to get a little more out of my sessions. The Orion nebula responds well to HB, OIII & UHC at high power. I would wager a decent sketcher would be able to bring all those elements together really well.

try campbells H star Rob, it's an interesting object although as it is a planetary nebula, it is concentrated so bound to be brighter. Would be interested how it responds to higher power, say around x120/180 ish in your apo. I do think your c8 with a focal reducer is your best bet.

With John here in the main, the filter has limited use. I have the identical list to what Don posted but I have either struggled or not needed the Hb filer with them. EDIT; The key to nearly all HB targets is very dark skies, moving on. This is my opinion and not fact btw. Where no comment, I have not yet got around to trying with an HB. I used a 14" F5 dob and eyepiece giving a 5mm exit pupil: 1. IC 434 w/B33(HORSEHEAD NEBULA) Absolutly needed2. NGC 1499 (CALIFORNIA NEBULA, naked eye and RFT) UHC also works, not a huge difference between the 23. M43 (part of the Great Orion Nebula) Need to try this again so no comment4. IC 5146 (COCOON NEBULA in Cygnus) difficult, I wasn't sure if I saw.5. M20 (TRIFID NEBULA, main section) 6. NGC 2327 (diffuse nebula in Monoceros) 7. IC 405 (the FLAMING STAR NEBULA in Auriga) UHC works fine for me8. IC 417 (diffuse Nebula in Auriga) 9. IC 1283 (diffuse Nebula in Sagittarius) 10. IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus)11. IC 2177: SEAGULL NEBULA (Diffuse Nebula, Monoceros) 12. IC 5076 (diffuse nebula, Cygnus)13. PK64+5.1 "CAMPBELL'S HYDROGEN STAR" Cygnus (PNG 64.7+5.0) Superb with the HB, jumps right out at you. Very difficult without a filter. Not tried a UHC though, suspect it will do well on it.14. Sh2-157a (small round nebula inside larger Sh2-157, Cassiopeia)15. Sh2-235 (diffuse nebula in Auriga).16. Sh2-276 "BARNARD'S LOOP" (diffuse nebula in Orion, naked eye)17. IC 2162 (diffuse nebula in northern Orion)18 Sh2-254 (diffuse nebula in northern Orion near IC 2162)19. Sh2-256-7 (diffuse nebula in northern Orion near IC 2162)20. vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177)21. Lambda Orionis nebular complex (very large, naked-eye)22. Sh2-273 "Cone" Nebula portion south of cluster NGC 2264 The objects that respond are limited and the objects that only respond to HB are even more limited. You will get a better response using equipment which gives a large exit pupil at 5mm or close too that, these are very tight band pass filters and you need to let a lot of light hit your retina. I think a slow (F6 or slower) will struggle on nearly all of those objects but I would be interested to hear how you get on. Dispite all my perceived limitation of the HB filter, I won't get rid of it. Steve

Sounds perfect if I am honest, a lot of thinking to do and probably gear to be moved on if I do decide to go ahead. Thanks for the response though, I know enough now to make a decision.

Is that an ST4 to USB cable Elp? And what about alignment, any change to that process?

I have my eye on this mount, lightweight, apparently tracks very well and excellent capacity so really peaking my interest. I have found a very useful thread on CN regarding it but wondered if anyone on here has a HEM15 that they use with the ASI air plus. Anybody own an iOptron HEM15? - Mounts - Cloudy Nights There is mention to connecting the air+ in the thread but I wasn't 100% what the contributors were referring to. So in particular I want to clarify how do you connect the Air+ to the mount ie USB to ST4 cable / ST4 cable / a.n.other cable Is the setup process to polar align the standard way using the phone/tablet app. Anything else really. EDIT As per title I edited, this also refers to the HEM27 & CEM28 users as apparently the mount protocols are the same. A purchase isn't imminent but just doing my homework.