tooth_dr

Anyone check over my figures please? I'm in the process of chatting with a friend who works with metal, to modify the Nikon adapter. If my measurements are right, I can free up at 4mm by threading my Nikon adapter direction into the EFW2 base plate, and still be clear of the filters. This will give me a back focus distance of 44mm, so that should let me away?

Thanks Rodd 👍🏼

Do you think it would be possible to cut an m54 thread into the outside of the Nikon adapter to screw it 1.5mm into the EFW2 cover. I have a spare EFW2 so I could modify it too.

I ordered a Nikon to M42 adapter, and it arrived yesterday. It is about as slim as possible, with only 1/2m or less between Nikon lens protrusions and the metal of the adapter. I'm not exactly sure where to measure from, I'm assuming that the Nikon body metal edge is where I need to achieve 46.5mm back focus. EDIT: I've checked the flange point, and I was incorrect in my first measurement. So my totals are 9.4mm for the adapter, the EFW is 22.0mm, and the back focus of the QHY9 is 17.3mm. I've the EFW2 adapters arranged in such a way that that add 0.0mm to the connections. So my total length is 9.4+22.0+17.3mm = 48.7mm. If I add in the 1/3 of the 2.0mm filter thickness this gives me another 0.7mm to spare, which gets me to 48.0mm However it isnt focusing, but very close. I had hoped that the fact the lens focuses past infinity would give me a little bit to spare but it doesnt give me enough. Either new filter wheel or new camera by the looks of things as I cant see anywhere to take 1.5mm off it. What are my options and importantly do I have my calculations right? Adam.

Wow I didn’t know where the squid was located and didn’t want to ask. That actually really enhances the image Richard. Great job.

I think it looks great. It has a nice depth to it, and hasn’t been over worked. There might be a slight collimation error due to the split diffraction spikes.

I didnt bother getting up due to the forecast. Sounds like it wasnt great, but still really great to read these reports. I did perservere with the Leonids on Monday. Out of 300 DSLR images - I grabbed one meteor!!

I used data from two nights, and there was a different rotation of the tube relative to the sky. So that produced two sets of spikes. The coloured spikes correspond to RGB data from the reflector combined with lum data from the same night, the non coloured spikes are just from lum on that different night. Below is reflector lum (epsilon) and refractor RGB (ED80). There are double spikes here due to dodgy collimation (when I bought the scope)

That is nice delicate procession, and the phallic region is particularly nice. If you get a decent methodology please share Donal! Adam.

Also Wim, Ive combined reflector lum with refractor RGB, and obviously the spikes arent coloured. This is kinda visible in the image below cropped from my M45 image

Well not really John. I never intended to use an OAG so that question I just dont know the answer to.

Ha would be the most common 'first' NB filter. The Ha will work well with your DSLR, the other ones not so much. Using NB filters with a colour camera will always be a compromise, but having said that the results can still be excellent. The DSLR will need a 2" filter, your new CCD might not need 2", depends on the sensor size. You could buy a 12nm EOS clip in filter - they sell for £100 second hand. Use that for now, then when you upgrade to a CCD, sell that filter and reassess your needs. Thats my take on it! Adam.

Hi John. With the Tak I'm after a backfocus of 56mm (+0.7mm to account for the filter thickness). This was achieved with some spare space, so I ended up needing a spacer. The thickness of the EFW3 is 21.8mm and the backfocus of the camera is 17.5mm, this gave me 39.3mm. So I had roughly 17.5mm to fill in using an M54-M54 adapter, and an M42-M54 adapter.

Thanks John. I just bought an Atik EFW3, so I figured it was just make more sense to use the Atik 383L. I've it spaced to perfection now so I wont be touching it!!

Here is a comparison of RGB spikes from the other night:

Thanks Adam, do you think there would be much improvement with the other filters?

Thanks Adrian. I’m never sure how far to push the colour saturation, it’s hard to find that balance.

duplicate

Just using regular 7nm NB filters. I was aware of these but not sure how significant a difference they would make. What makes you ask - low contrast? Was a very big moon close by. Dont think my wife could handle me spending £600 for the set on highspeed NB filters EDITED: /Now reading stuff like this. Looks like some more overtime needed BAADER 2" F/2 HIGHSPEED FILTER SET The 2-Inch f/2 High-speed Filter Set by Baader Planetarium: Baader's new f/2 High-speed Narrowband filter sets contain H-alpha, OIII, and SII filters and are made specifically for the sensitive requirements of exceptionally fast astrograph optics, such as HyperStar, RASA, and extremely fast instruments from TEC, AP, ASA, etc. Ordinary narrowband filters generate a heavy loss in transmission because of the strong CWL (center-wavelength) shift. In severe circumstances, the CWL even shifts out of the FWHM (full width half maximum). As a result, these filters have a CWL-preshift which flawlessly matches f/2 to f/3. Furthermore, the FWHM is enhanced. Despite the typical line broadening with such fast optical trains, these filters are still able to produce peak contrast. These filters permit the effective use of tremendously fast optics for maximum contrast imaging of emission nebulae for the first time. Compared with a regular set of narrowband filters, using these high-speed filters between f/1.8 and f/3.5 will exhibit drastic improvement.

LRGB image from the past couple of weeks. The camera was changed and scope was moved between exposures - the downside to a reflector Had to crop it a bit too. It's looking like rain for a few days, I just want to practice on this data. I'll need to address the star sizes soon ( I keep ignoring them) if I want to progress in this hobby, but even getting a decent RGB combo was an achievement for me. Looks a bit soft. Adding Lum to RGB I'm struggling again. I had a lot of luminance but limited colour data. RGB was 5 x 300s per channel. A small 2 x 2 panel mosaic was really do this target justice. Comments welcome Adam.

Adrian, that HH M42 image is stunning. It's inspiring me to dedicate this winter to a decent colour mosaic of that region! NGC1499 is just rippling, splendid.

Top quality David, delicate but contrasting at the same time!

Lovely image, very well framed.

It’s a tricky one to see. Have a read here to confirm your sightings 👍🏻

Thanks Sean! Makes sense! This is a luminance diffraction spike from another image i took