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alan4908

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alan4908 last won the day on January 18

alan4908 had the most liked content!

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About alan4908

  • Rank
    Proto Star

Contact Methods

  • Yahoo
    alanmarsh4908@yahoo.com

Profile Information

  • Gender
    Male
  • Interests
    Astrophotography ! ....at the moment I'm concentrating on deep space imaging
  • Location
    East Sussex
  1. alan4908

    Northern Trifid (NGC1579)

    Thanks Steve - yes, the UK weather is definitely not optimal for astro imaging, which is the main reason I choose to construct an automated set up to try to overcome this issue (I also enjoy my sleep ). Thanks Carole -parts of East Sussex are quite dark and I'm somewhat fortunately to live in an area that is quite dark (no street lights etc) - as you say, for this particular object, you do really need access to a site that is reasonably dark. Thanks ! Thanks for the complement Richard. Alan
  2. NGC1579, better known as the Northern Trifid, is located in Perseus and is about 2100 light years away. There's lots of dust around this region and the starlight reflects this to produce blue reflection regions. The red glow is created by dust scattering and the subsequent reddening of the light from an embedded young and massive star located within the nebula. I was a little surprised to find that my automated set up had been slowly gathering data since mid November - I guess this demonstrates how poor the UK weather has been of late. Anyway, 2 months later, I finally present my first attempt at an LRGB image with the Ha blend into the red channel. The image was taken with my Esprit 150 and represents about 18 hours integration time. Alan L:23, R:15, G:15, B:15, x 600s, Ha: 13 x 1800s, DARKS: 30, FLATS:40, BIAS:100 all at -20C.
  3. alan4908

    NGC 1333 - high resolution New Year's delight

    An exceptional image Barry you must be very pleased with the result of your new high resolution set up. For my UK site, I've also found that around the 0.7 arc seconds/pixel seems to be the optimum for extracting the maximum resolution from DSO objects. Alan
  4. alan4908

    Best autofocus software?

    Hi Martin Well, I started with MaximDL autofocus routine and moved to FocusMax when I decided to automate my obsey with ACP. I find it very reliable and consistent, however, I always use it in the mode of finding a suitable focus star with the L filter near the zenith. The reason I do this to minimize atmospheric effects which impact the variability of the focus precision. I also have it set in focus convergence mode where it attempts to overcome seeing effects. For my other filters, I use filter offsets - again I found this very reliable. Choosing a suitable focus start is very important since you need to be on the linear part of your cameras dynamic range, I always let ACP select this. Alan
  5. alan4908

    The Great Barred Spiral Galaxy - NGC 1365

    A beautiful image and wonderful colours. You've also got a lot of faint background objects here, well done. Alan
  6. alan4908

    IC1396 - SemiRGB/narrowband combination

    That is an excellent result. You have excellent contrast and details from the narrow band data + natural looking colours. Alan
  7. alan4908

    M31 4-panel mosaic

    An exceptional image - very impressive indeed. Alan
  8. alan4908

    Stability of PA alignment

    Thanks for the replies - It is good to know I'm in the company of professional observatories . I will assume that the vast majority of the effect is from movement of my Pier which arises due to the changing moisture clay content. Thanks vlaiv - however, what I didn't understand from the (very interesting) Wikipedia article is how you calculate the time period X to give 1 arc minute misalignment. As you indicate, I presume this is will come out to be many years, so compared to my Pier movement it will be insignificant. I normally try to operate at a PA of 1 arc minute or less - as you say, it doesn't take much to knock this out - thankfully Earth tremors in East Sussex are somewhat rare ! No, I don't take the scope off the mount, I also don't drift align to obtain my PA. To initially polar align, I use a piece of software that instructs my mount take 10 images which are then plate solved over various positions of the sky. The plate solve results are then synched to the mount which builds up an sky model error map of RA and DEC. To perform the PA, I select from a list of polar alignment stars which the mount provides and the scope slews to the selected star and then its simply a case of adjusting the alt and azimuth controls until the star is centered in the CCD. It's quite a simply process and it appears to give an PA accuracy of a few arc seconds. After I've done the initial alignment and because I image unguided, I get the software to repeat the procedure for 100 images which builds a very comprehensive sky model for the entire sky. I've found that to image 30min subs at 0.7 arc seconds/s unguided I need a PA better that 1.5 arc minutes, in addition my Pier also needs to be very horizontal (unlikely a normal equatorial mount where this doesn't matter). Thanks. I haven't noticed any similar effects but I'm only at 0.7 arc seconds/pixel, its also probably helps that my observatory floor is semi- isolated from the Pier.
  9. Hopefully, this is a straightforward question. Assume that I align my scope with zero PA error. I come back at time X during which time I haven't touched anything on the scope/mount. In addition, assume my pier does not move or my mount/scope does not slip. Approximately, how long does it take before my PA is 1 arc minute out of alignment ? The reason for my question is that I notice that my PA gradually degrades over time, I believe this is due to my pier/mount/scope moving slightly but I wanted to check that I haven't missed any alignment factors that would accumulate due to the motion of the Earth. Since I don't alter the configuration of my imaging scope, I'm almost 100% convinced that I experience very slight Pier movements which change with the weather conditions- this is explained by considering that whilst my Pier sits on a substantial concrete block, the concrete block sits on clay soil. Alan
  10. alan4908

    Electrical layout for ROR observatory

    Hello - a bit of input concerning electrics inside my own observatory - you can see what all this looks like by going to my album......................... In the design for my observatory I also decided to keep all the mains in the warm room and low voltage dc to the main section. Mains AC: I asked a local electrician to run armoured cable from the house to the observatory, which is buried in a trench. This terminates inside the observatory onto a master switch which supplies AC via numerous double sockets. It's amazing how many sockets you need, don't skimp on these. The incoming mains is protected by a simple 13 amp fuse and a surge protection circuit. DC: The main 12v DC is supplied by a high quality power supply which powers about 90% of my astro equipment. This supplies power to a low voltage DC consumer box. The box contains fuses for the various pieces of astro kit. Lighting: I went for low voltage LED lighting strip/tape (which is dimmable and colour changable). . RCD: I don't have a separate RCD monitoring since the house consumer unit monitors all mains circuits. USB: I have two powered USB ports which have proved quite reliable, one inside the warm room and one at the pier. Data cables: the observatory is connected to the internet via mains over ethernet. I also have a separate LAN switch inside the room. UPS: I have an UPS for my mount, which supplies power for an adequate time to allow me to manually power it off in the event of power supply failure. Electric roof: since I'm into automated imaging, I have an electric roof which is based on a garage door opener. Roof sensors: I have sensors on the roll off roof - these inform the PC if the roof is open or closed. Mount sensors: since the roof can hit my scope - I have sensors on the mount which inform the PC is the scope is in the (safe) parked position. The roof can only close and open if scope is in the parked position. Rain sensors: I have three independent rain sensors. A main one from HitechAstro, which has never failed, but is reliant on my PC and mains power. An independent backup which is reliant on mains power and a backup to the backup which is battery powered. You may think is over engineered but the last thing I wanted is rain inside my observatory ! Alan
  11. alan4908

    Deep Sky III

    Images taken with a Trius 814 and a Esprit 150
  12. I'd suggest you try the Repaired HSV separation with the default values but the pixels set to 15. This will give you an orange star when you view the resultant image (unstretched). In terms of stretching, I personally never use masked stretch since I don't like the result. Rather I would suggest using arcsinhstretch for the RGB and combining it with a synthetic Lum using LRGB combination. Alan
  13. alan4908

    Heart Nebula Hargb

    A very nice image Richard. I really like the star colours - I didn't quite understand the brief explanation above concerning your processing technique on these. Are you able to explain a little more ? Alan
  14. alan4908

    Melotte 15 the Heart of the Heart

    Very good. I do like the star colours and the 3D effect of gas and dust. On the black point - if you are concerned about loosing some of the faint dust you might want to try this (Adam Block) technique if you process in PS. Copy the image three times so you have a top layer, a middle layer and a bottom layer. Apply Equalize to the bottom layer (Image->Adjustments->Equalise), set the second layer blend mode to multiply. Adjust the top layer opacity slider to taste. This allows you to move in the black point without impacting the visibility of faint dust. Alan
  15. alan4908

    Ring galaxy (NGC7217)

    Thanks Tony - I was very pleased with the amount of detail revealed, which was assisted by my use of Deconvolution of the Lum data in Pixinsight. I found getting sufficiently saturated colours more difficult, probably due to the faintness of the object. Alan
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