Posts Made By: Anthony Ayiomamitis

Art et al,

Can someone please inform me if the Tak FSQ 1.6x barlow yields an effective focal length 1.6x that of the native 530mm focal length for visual or imaging purposes?

I have tried using my TeleVue 2x Big Barlow with my FSQ and I got an amplification which translates to a factor of 2.67x. A friend mentioned that the "2x" is for visual work (ie. eyepieces) and not imaging devices where the imaging chip is futher back.

Where do things stand with the Tak FSQ 1.6x amplifier ... visual or imaging?

Thanks!

Anthony.

Dear group,

Approximately two weeks ago we had the announcement surrounding the latest exoplanet discovery. To be more specific, two independent exoplanet hunting teams (WASP and HatNet) announced their discovery of an exoplanet in Aries which has the least mass of any exoplanet discovered to-date and which is hosted by an 11.89 magnitude K-type dwarf star.

Since the WASP announcement preceeded that from the HATNet project team by a few days, it received priority in the joint naming of the latest find to WASP-11/HAT-P-10.

For the first amateur light curve surrounding the latest discovery, I kindly direct you to my result from early this morning based on 4.5 hours total data.

http://www.perseus.gr/Astro-Photometry-WASP-11-20081009.htm

My newly arrived ST-10XME showed off its stuff for first light in a most impressive fashion and as indicated by the quality of the light curve. There were transparency issues all evening due to a brief weather front making its way here and which made things really ugly near the end of my session.

Anthony.

Dear group,

Here is a rarely imaged Seyfert galaxy only seven arc-minutes away from bright Mirach (beta-And, mag 2.06) from last night:

http://www.perseus.gr/Astro-DSO-NGC-0404.htm

The result came out much better than expected, for there were strong winds and I purposely did not stick around for very long therafter so as not to endanger further my equipment.

Clear skies!

Anthony.

Dear group,

The dwarf galaxy NGC 147 in Cassiopeia and member of the Local Group is one of approximately 60 galaxies for which (extragalactic) globular clusters have been detected. More specifically, NGC 147 has been found to contain four clusters dated to be approximately 9 billion years-old and ranging in magnitude from 16.98 to 21.10. They are appropriately named Hodge I to IV and after the principal author of the 1976 paper which described their properties.

For a result based on four hours total time and which includes these four extragalactic globular clusters, please see http://www.perseus.gr/Astro-DSO-NGC-0147-GCS.htm and remember to click on the hyperlinked image for the same result but with better scale.

Back in a few days with another member of the Local group but with eight member globular clusters.

Clear skies!

Anthony.

Dear group,

It took a few days due to cat-and-mouse games with the clouds at night to process my results from a few nights ago involving the dwarf galaxy and member of the local group NGC 185 in Cassiopeia.

Aside from being bound to another dwarf galaxy, NGC 147, less than one degree away, NGC 185 is also known for its eight globular clusters which range in magnitude from 16.6 to 19.7 and are aged from 5 to 10 billion years-old.

For the result which includes all eight globulars, please see http://www.perseus.gr/Astro-DSO-NGC-0185-GCS.htm (the image is hyperlinked and clicking on it loads a larger photo).

For a similar result from last year (NGC 205) and which includes fifteen clusters in and around NGC 205, please see http://www.perseus.gr/Astro-DSO-NGC-0205-GCS.htm .

Please no enquiries as to the availability of my AP160! :-)

Anthony.

Dear group,

Aside from the stunning double cluster in Perseus, we have a large number of other impressive open clusters in this rich constellation.

A few days ago I had a sucker hole with good transparency but questionable seeing and where I pursued NGC 1528, one such rich open cluster in Perseus. This was my fourth attempt at NGC 1528 and it is still not quite where I would like it to be but certainly better than the three earlier efforts.

I have checked around the internet for other results involving NGC 1528 and only to find a very small number of efforts.

For my latest effort based on two hours total exposure time using luminance layering, I kindly direct you to http://www.perseus.gr/Astro-DSO-NGC-1528.htm and which taken with an AP160 and ST-2000XM. My prize camera (ST-10XME) is now back from some service work and will be used for another crack at this bright and rich open cluster (weather permitting).

Clear skies!

Anthony.

Folks,

Can I get some feedback on this particular refractor? Aside from needing an MPCC, I have read reports that a DSLR will not reach focus.

Also, how bad is the chromatic aberration?

Thanks!

Anthony.

Folks,

Can we please try and remain on-topic within this group? During the past few weeks we have had a few threads surrounding equipment and which is most appropriate in other equipment-related groups including TeleVue and refractors.

I remind everyone that the description for this group reads "DEEP SKY IMAGERS have their own unique Imaging and Processing issues - Now they have their own FORUM" and it is both frustrating and tiresome seeing LENGTHY threads which not only do not belong here but have other groups here on Astromart where they are ideally suited.

No, I am not the administrator but an interested reader and participant!

Anthony.

I saw the same ad ... it did sound strange. :S

Anthony.

Dear group,

Last night I finally had my chance to set the Mewlon 210 loose on the night sky. I collimated the optics about two weeks ago but the intervening weather did not allow for any sort of work under the starry sky.

Both the seeing and transparency were quite flaky last night with periods of very good seeing and transparency as well as the converse. To this end, I decided to forego my primary target of interest (NGC 4088 in UMa) and pursued some test exposures involving one of my favourite pair of interacting galaxies, namely M51 in CVn.

Since these galaxies beg for portrait framing, I set the camera with a 270-degree rotation from its "home position" so as to also have a really good guide star available for me to use. However, this is where I experienced my first disappointment, for the CCD camera (ST-10XME) was obstructing the view through the finderscope and which is placed on top of the telescope and in contrast to other manufacturers who allow for placement at 45 degrees to the left or right. I understand and appreciate having the finderscope atop the OTA so that it can also be used as a handle when transporting the OTA but it becomes useless when a CCD camera is placed in portrait mode.

Once everything was aligned 15 minutes later, I experienced my second disappointment. The Moonlight two-speed focuser impresses the user with its fine construction and sweet smooth movement when using the fine adjustment knob. However, there is a lot of play when the CCD's camera 2" nosepiece is inserted. For a moment I could not understand why my spikes (due to the vane) were duplicating on the computer screen but then I realized that it must be a flatness problem (ie. the camera not being square to the plane). To make matters worse, my optical alignment two weeks earlier did not consider such a potentially hidden problem.

After fiddling around with the securing of the CCD camera onto the Moonlight focuser, I was able to get it square but the focuser then started to roll on me. Tightening a couple of screws seem to fix this problem and I was finally in a position to start imaging.

Attached is my first result using the Mewlon 210. It is based on two hours total exposure time (12 10-min subs) taken at an image scale of 0.58"/pixel and which has been resampled to 50%. A DDP non-linear stretch was applied so as to compress the dynamic range and thereby allow a greater amount of detail to be presented simultaneously.

When aligning the optics two weeks ago, it was quite obvious they were razor sharp but the issue of flatness always remained at the back of my mind. The manual states an 18mm image circle for the Mewlon 210 at its native focal length of 2415 mm. Inspection of the attached image would seem to confirm this to be generally the case since the stars are very slightly deformed at the corners.

I run CCDInspector very quickly through some of the subs and the software suggests tilt as well as some misalignment for the optics. As a reference, I checked some test subs taken with my AP160 over the winter during adverse conditions and it is obvious that I still need to work on finetuning the alignment for the optics.

For my AP160, the tilt of the camera was 0.0", the optics were off by 0.1" and the flatness was reported to be around 7.5-7.8% (depending on the sub being used). From last night, I was getting a tilt of 0.8 to 1.1" for the camera (thanks to the Moonlight focuser), 8" for the alignment (or misalignment) of the optics and 24% for the field flatness.

It is obvious that I first must work on the camera being square before I tackle the issue of optical alignment. The Moonlight focuser uses three screws and a compression-style mechanism but it is not working as well as my AP160. Since the Mewlon is characterized with minor mirror shift during focusing (and refocusing), the Moonlight focuser did solve any such shift which would have occured otherwise.

Something I should also mention is the issue of temperature stability. I purposely stuck around for a few hours so as for the temperature to drop (it usually hits bottom around 3 AM local time) and I was impressed by the Mewlon. It is quite stable even with a fluctuation of four degrees in the ambient temperature and I suspect this is due to the open-tube design. As is always the case, I start preparing for each evening's session two hours earlier and which indirectly provides ample time for the tube to cooldown. With last night's problems due to the finderscope and Moonlight focuser, these two hours were further extended by around 45 minutes.

Anyway, last night's effort was more for testing the waters than anything else and which proved to be quite acceptable in lieu of the various problems encountered and various finetunings outstanding as a result.

Anthony.