Venus and Mercury from Spain

Tom Boles dicovers Supernova number 129!

Tom Boles discovered the Supernova below on Thursday 4th March. Here is an image I took of it on March 7th.

28th February 2010 - Abell Clusters

I have been adding galaxies from Abell Clusters to my Galaxy Search Library. This was one of the Galaxies - NGC 891. Here is the information for NGC 891 provided by The Sky

 Object name: NGC 891
Magnitude: 10.1
Equatorial: RA: 02h 23m 12s   Dec: +42°23'48"(current)
Equatorial 2000: RA: 02h 22m 33s   Dec: +42°20'50"
Horizon: Azim: 298°06'43"   Alt: +33°09'00"
Size: 11.7 x 1.6
Transit time: 16:01  Always above horizon.
Object type: Spiral Galaxy
Source catalog: Revised NGC
Blue mag: 10.9
Constellation: AND
Surface brightness: 13.1
Remarks: IRAS02195+4209
Dreyer description : Remarkable! Bright, very large, very moderately extended 22°.
Position angle: 22°00'
Hour angle: 05h 58m 09s
Air mass: 1.83
Sidereal time: 08:21
Click distance: 0.0000
Catalog number: 891
Celestial type: 8
NGC/IC: 0
Catalog: 1

Using a plate solution to centre an object and synch the telescope.

Friday night (19th February) was clear until about 1130 p.m. I managed to image over 100 galaxies. It is so much easier now with the centred images but I have a long way to go to build up a sufficient library of reference galaxies with so few clear nights here. I have been experimenting with synching into the T-Point model to see the effect. This is not a recommended approach but I believe that it is quite an effective method of keeping objects centred. I think the ideal way of adding points to the T Point model is to take an image, solve the plate and then synch into the T Point model if necessary or map on the image link centre rather than spend time centring a star and mapping that. If you have a good plate solution this is extremely accurate and also avoids identification errors – it just does not matter where you are pointing. This was the first random area of sky that I imaged, synched on the image link centre and mapped into the model.

(Unknown 1)

 

Carrying out a plate solution gave 19 stars used with an RMS position error of  0.09 arcseconds.

Here are the above image and the chart produced by the Sky to confirm the pattern recognition

I now added labels from "The Sky" which identifies many of the stars on my original image.

 

The image link information in the table below gives me the actual  centre of the image (i.e. where the telescope is actually pointing so by Synching on this position corrects the pointing error on the telescope at those coordinates.

 So once the Synch was carried out all successive images that night (100 plus) were exactly centred.

Leyland Observatory Primary Optics upgraded

No - I haven't bought a new telescope - the power of laser technology has upgraded my distance vision to one line better than 20/20!

The operation was on the 2nd January and I am now able to see the stars with the naked eye as actual points of light for the first time in my life! Unfortunately I still have to wear reading glasses - an age thing I am afraid! Strangely I can also see the colour of the stars more clearly - Aldebaran and Betelgeuse are really red.

I have to be careful for a few weeks but the improvement was immediate.

A few days after the operation I performed a mapping run (following the laptop failure) that now has the telescope centering objects in the 11x11 minute field of view. (125 stars mapped).

The objects are centred to within about 45 seconds of arc in the region of sky (i.e. just left of the meridian) that I use for supernova searching.  Last night (17th Jan 10) I tried to precisely North align the camera but clouds kept appearing and I abandoned it for the next clear opportunity. The images were solving nicely with over 20 star matches which were able to tell me the current camera position angle. Once that is done I can resume my searching.

I am looking forward to my trip to Almeria in Spain in April to assess the skies there and will be taking my ETX 90. Hopefully I will be able to try it out with my DSLR to take some images. Almeria is the driest part of Europe (Lawrence of Arabia and the Spaghetti westerns were filmed there - as well as Raiders of the Lost Ark I believe). I am driving down with Harry the Westie!

I have really only used the ETX for partial eclipses - it worked really well for that  - short exposures only of course. I purchased the ETX on ebay (also where I bought my car) and got a very good system that had had all the "tuning" following I believe Mike Weasner's suggestions to tighten it up. The package included balance weights for a camera and a solar filter (mylar type). My DSLR worked very well with this to give some good images.

Telescope Pointing

Unfortunately my telescope pointing had been lost so I have had to start again with TPoint to map stars so that corrections for the mechanical imperfections of the mount can be calculated and corrected for. I need to have the target in the centre of the image every time so that the image can be blinked with the library master. I have also changed to f/10 which gives me an image that is 11.43 minutes square requiring greater pointing accuracy  so I am trying to get the polar alignment to be more accurate so that it points at the refracted pole. I have had 3 runs at the mapping with 17 stars per run having applied the 6 fixed terms and 4 harmonic terms. TPoint is now indicating that the telescope is pointing 23 seconds of arc above the pole whereas I estimate by interpolation that I need this to be 44.76 arcseconds for my latitude.

Dome Laptop fails

Disaster struck last week when my dome laptop refused to switch on and was deemed to be not worth repairing. Fortunately all data was saved but I had to purchase a new one. Much time was spent in reloading software onto the new Windows 7 computer. As always not everything worked at first causing some stress. Updating the Software Bisque (SB) software to the latest versions and looking at Windows 7 issues discussed on the SB forums eventually resolved these problems. Now all I need is a clear night to be able to check that the telescope pointing has been maintained.

North aligning the camera.

I was taken by surprise last night (14th November) when I discovered that it was clear at 11pm - I should have checked earlier!! However I managed to align the camera properly before the inevitable clouds set in at 1 a.m.

The new external focuser is shown below

The thumbscrew on the top of the focuser can be loosened to allow the entire focuser and attached camera to rotate to get the camera aligned to have North at the top.

 The image above shows the Crayford Focuser attached to the LX200 and to the camera.

The Crayford now takes over the focusing role from the LX200 and so the mirror is clamped as shown in the image below which shows the fully (firmly but not putting any stress on the mirror) tightened spring on the focus lock.

Images were taken to determine the Position Angle - this is the first image of Globular Cluster Herschel - H201-1.

 The plate solution gives a Position Angle of 1.98 degrees.

I adjusted the Position Angle once more - took a random image - and solved the plate.

Here are the actual image and "The Sky" solution.

 As you can see the alignment with North is good - as the North arrow is vertical

The Plate Solution gives the detail

The position angle is now 0.31 degrees - this is near enough!!

Testing Imaging at f/10 instead of normal f/6.3

At my normal focal ratio of f.6.3 images are approximately 20 minutes square which gives a good field of view but means that many galaxies are quite small. Also there does tend to be vignetting of the image. Whilst incorporating a new external focuser to get around image shift problems I thought I would try imaging at f/10 and check the practicality of centring the images (at the smaller field of view) for a galaxy run. On 9th Nov the sky was clear with drifting cloud which eventually became thick cloud - limiting the test. I tried it out with one object - NGC 744 - see the image below.

Clearly it is quite well centred. Here is the Deep Sky Survey Image - courtesy of The STScI Digitized Sky Survey.

The above image was obtained from STScI by completing the table below

The plate solution is shown here - 21 matched stars - RMS 0.08 which is a good astrometric solution.

This (as represented in the first image above) shows that the camera is not North aligned  - the Position Angle is given as 347.57 degrees. There was not time to rotate the camera to the 360 or 0 degree position as clouds set in. The matched stars on the image are shown here.

This is the image plotted onto the Sky Chart solution showing that it is indeed NGC 744

 and the Object Information Box

and the exact match of the Sky chart to the image. Note the direction of North corresponding to the discussion above.

Galaxy Run 16th October 2009

I managed to image 329 Galaxies tonight - some of which were obscured by cloud I might add which drifted by from time to time!