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Posts posted by fwm891

  1. Interested in comments on an 8 inch f8 RC, looking to get one.

    I had a few years back an Altair Astro (GSO clone) which I sold (why!!!) and I'm now looking at it's replacement. I see FLO do their StellaLyra, RVO do an iOptron Photon and there are others. Just wondering on other good/not so good views on them...


  2. After waiting for these to get out from behind trees the weather turned quit murky so I'll put this down as a Mk1 attempt and try again on another night...

    Shot 25x 300s subs but could only use 16.

    Just about make out the tails but definitely needs clear dark skies.


    • Like 5
  3. 1 hour ago, Laurieast said:

    Where does the lolly stick fit into all this?

    Nice deep field!

    It turns out that the WO version of a Vixen dovetail bar is narrower than a standard Vixen dovetail bar so when mounted the whole optical train is shifted over to one side and unless you add extra weight to the opposite side it won't balance. A loolly stick shifted the OTA assemble back to it's central point...


    • Like 1
  4. 2 hours ago, AbsolutelyN said:

    Loads of galaxies here looks great. I've never heard of a mono DSLR before though. How does that work? Has the sensor been swapped out? 

    The mono DSLR. The sensor has been striped of all filters (bayer matrix) and all glassware. The chip is essentially bare. Ultimate full spectrum mono mod.

    • Thanks 1
  5. I've had a couple of issues with PHD and balance with my CEM25P / WO ZS73 combination lately and spent quite some time getting the balance right yesterday and put it to a test last night. (A lolly stick proved the best solution!).

    12x 300s subs were shot at 1600 iso on a mono modified Nikon D5100. Images were processed in PI then resized in PS before posting here.


    Plate solved image: https://www.astrobin.com/xodxry/?nc=user

    • Like 6
  6. 3 hours ago, steppenwolf said:

    Can't be sure that mine was a Charles Frank but it would have been 60 years ago that my parents bought me a black cardboard tubed refractor via the 'Look and Learn' magazine. I remember well that I had to be VERY careful when focussing inwards as it was all too easy to blow the single lens off the front as the white plastic retaining ring was not a great fit!!

    Yes I remember blowing the lens off the front too. Lots of tape I remember using now...

  7. About 60 years ago (in a galaxy far far away!) my Dad bought me a Charles Frank refractor which consisted of two cardboard tubes. At the front of the bigger tube was a single bi-convex objective lens (uncoated) at the other end of the smaller tube a lump of rubber with a tiny little eye lens molded into it.

    It was advertised in one of the daily papers in a little ad in the classified section.

    Everything viewed showed red and blue fringes but It got me hooked on this hobby.

    Anyone else have the same beinnings?

    • Like 2
  8. 8 minutes ago, Adreneline said:

    Thank you Francis.

    I know the 294/135 is massively oversampled but sometimes you have to focus on the big picture ;) 


    Seeing your image I'm just setting up a sequence in SGP for my 85mm f2.8 and ASI533 combination....

    • Like 1
  9. 5 hours ago, PhotoGav said:

    I like that a great deal! Fascinating and different. Where in Ursa Major is this? It looks like it is crying out for some vast mosaic to show the IFN web in context!

    Thanks Gav, This is part of 'The volcano nebula' and centred around RA 09hrs 30min  Dec 70° 11mins

    • Like 1
  10. Good session last night, sheltered from the wind I continued my current fasination with IFN's in Ursa Major.

    This image captured last night (5th - 6th April 2021) comprises 40x 300s subs and processed in PI using luminance masks.

    Scope: RASA 8, Mount iOptron CEM60, Camera ASI533, Filter Baader UV/IR cut

    Software: capture SG Pro, image PI.

    Hope you like


    • Like 9
  11. 10 hours ago, gorann said:

    Nice image Francis! Still a bit noisy but maybe you are fighting light pollution and IFN is really faint, so it is a tough task. What is your Bortle / SQM?

    Since the RASA only has one mirror, all images are mirror images so I first had some problem orienting myself in your image. I always flip mine when processing😉

    Hi Goran - I'm under Bortle 4 skies.

    I keep forgetting to flip images from the RASA.  Your IFN image containing M81-M82, have you dropped in another image of 81/82 onto your IFN image to retain the details?

  12. Mmmm, In P.I. I tend to stack each of the panes first,, use STF and Histogram Transform. Then SCNR to remove the green. DBE comes next to even out the backgrounds (pull the DBE process to the desktop and apply to each pane for consistancy). I then save as 16 bit tiffs and open them in PS CS3 to assemble the mosaic.

    Alternately if using APP just throw all your subs in the lights box, make sure you have mosaic mode selected and go and make coffee/watch a film while it sorts the whole image out for you...

    • Thanks 1
  13. 33 minutes ago, gorann said:

    Ed: Yes I can highly recommend a RASA 8 but you really should use it with a cooled circular CMOS camera. The new OSCs from ZWO and QHY are not far behind a mono and will make life easier.

    Francis: do you need to use an IR/UV filter for your OSC? My ASI OSCs (2600 and 071) have one built in

    Hi Goran, The ASI 533 only has an anti reflective coating on the chip cover glass and I've found that the UV/IR cut filter really reduces star bloat. Plus having removed the Celestron supplied protective filter it needs those 2mm of glass as part of it's optical train.


    • Like 1
  14. I have two intervalometers. They're both different so the best thing is to experiment.

    Your initial delay is for everything to settle down and stop vibrating.

    Next will be your exposure then the delay between exposures, then the count down through the exposures.

    One of my intervalometers wants me to set a time of 'x' seconds between each exposure - I normally set this as 8 seconds that gives the camera time to download/save the image.

    The other intervalometer wants me to set an exposure time (say 60 seconds) but when I set the delay between exposures it wants me to enter the delay value (say 8 secoonds as above) plus the exposure! so I have to set a delay of 68 seconds to get an 8 second delay after the exposure.

    Try different settings in daylight so you can see/hear what's happening. My guess is that your 2 seconds is not long enough for the camera to have finished saving one exposure befoore starting the next.

  15. 19 hours ago, irtuk said:

    Dumb question here but, hey its a lot of money to spend so I want to ask, with scopes like this celestron RASA where the imaging gear is at the front of the scope, do all the wires and gizmo's not get in the way of the light and impact the image?

    I am looking at getting a narrowband mono rig set up and, obviously I can see some incredible results on these forums from rigs but I would like to understand what you do with all the wires in setups like this.



    Hi Ed, I have a RASA 8 and yes the wires/cables do need some attention in use. Generally it's best to curve the cables to avoid diffraction spikes which is easy enough to do.

    I've not done any mono work with the RASA but your limitation is with the back focal distance with the RASA 8 either 25 or 29mm depending on where you measure from. There are filter draws that can be fitted allowing you to change filters manually which is quite simple. I use an ASI 533 Pro cooled OSC with my rasa and have now switch filters to a Baader UV/IR for broadband use and an IDAS NBZ for multi-narrowband captures.

    I won't now go back to mono imaging I'm having a far more productive time with my OSC. While many will say OSC cameras can't produce the quality of a mono system (and I probably agree to some extent) what the cooled OSC and the RASA combination allows me to do is capture images far more quickly - which suits me given the poor weather the west of the UK has to live with.

    A lens shield is a good idea with the RASA as the corrector plate sits right at the front.


    Hope that helps

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