Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.



  • Content Count

  • Joined

  • Last visited

Community Reputation

330 Excellent


About jimao22

  • Rank
    Star Forming

Contact Methods

  • Website URL
  • Skype

Profile Information

  • Gender
  • Interests
    Astronomy and astrophotography (solar and deep sky for the moment), ATM, DIY observatories
  • Location
    Ploiesti, Romania
  1. Hi, This is Iris nebula (NGC 7023 from Cepheus) trough my set-u for astrophotography: MN190 (mak-newt) on EQ6 belt-drive, ASI ZWO 533MC as main camera and QHY5II-L mono as guiding camera (OAG). The result is a stack of 41 exposures, 5 min each, from a Bortle 5 zone. Is amazing how CMOS camera and especially this one can work on a light polluted sky in full broadband. Acquisition, calibration with dark, flat and bias, debayering and stack - MaximDL, background neutralization, Photometric Color Calibration, ABE, SCNR, MMT, Histogram Transformation - in Pixinsight, Contrast, star reduction with 2 pixels and a bit of extra-denoise - in StarTools.
  2. After a while doing my best to have a very "perfect" set-up, highly automated, I find that doing pictures in the old way fashion is not bad at all. Moreover, you can take you light set-up with you and find dark locations or find places where transient phenomena occur (like ISS transit over Sun or Moon, sun eclipses or so) so to have such a set-up is not a bad idea at all. Having this in my mind, I prepared a set-up for this purpose. It is composed mainly from a iOptron Skyguider Pro and an Omegon 66/400 apo refractor. This set-up is in continuous improvement and seems to be a great idea. Anyway, first shots look great and this is one of them. Is about M42 (Orion nebula), 32 x 60 sec + 50 x 10 sec + 100 x 1 sec, processed in HDR using MaximDL for stack and calibration and PixInsight for HDR processing. No filters at all, only light frames - camera used is ATIK 460EX at -20 deg.
  3. Hi, This is the second target with my new color camera from ZWO. I have another shot to this target, from few years ago, but that one was a mono image, so I went back to it to see how it look like in colors. The rig used is my set-up from observatory - EQ6 belt-drive, MN190, OAG, automation with SELETEK and so on. The result is a stack of 32 x 300 sec images.
  4. Hi! This is my first image made with my new ASI ZWO 533MC camera. The target was M81 and the picture is a result of 50 shots x 300 sec, -20 deg. C, with my MN190 Maksutov-Newtonian astrograph on EQ6 belt-drive, from my backyard observatory. The sky is Bortle 5 on my location. The workflow for processing was the following: calibration with dark, bias and flats in MaximDL, debayering in Maxim again, alignment and stack in Maxim one more time and the rest of operations - MaximDL and StarTools.
  5. Hi. On 15-th of December I made some exposures to this lovely comet, very visible and very fast on the sky. So I took exposures 60 sec long with a pause between shots of 120 sec. The film is on the link, down bellow.
  6. These days I was at some star-party into the mountains and I finally made the tests with the ATIK 460EX. The field is the bigger I can obtain with what I have and due to this fact, I made some exposures to Amdromeda and Pleiades. Andromeda is 27x60s+30*x20s+30x5s. M45 is 47x60s. All procesed in PI without calibration, no filters at all and a Moon at 35%.
  7. Finally I had some decent weather and I made some exposures with my new rig: the home-made mount, the Omegon 66/400 and the ASI 174 camera. All images have the roundness less than 0.1 (measured in MaximDL) and I found that is no need for long exposures to have very good results. The final result is a balance between the shortest exposure you can do it with a good enough SNR (1) and the longest exposure you can afford with a good roundness (2). (1) depends on the local light polution, the contrast between the deep-sky object and the sky background (2) depends on the mount accuracy On my site I found that I need exposures between 30 and 60 sec for the best results with this set-up. Next tests - with the ATIK 460EX CCD camera. Much bigger... M92 - 9 x 40sec M101 - 20 x 60sec M51 102 x 40 sec M51 - detail
  8. Due to the very bad weather this spring time, it was very hard to find a good night for testing properly the new mount. But somehow I find a proper night being with one of my astro buddies in my observatory. I made a lot of exposures with Sharpcap but the darks and flats made with MaximDL didn't work to calibrate these images. I suppose is some kind of incompatibility in acquiring the data. Even if I tried to make new darks and flats few day later using the same Sharpcap, I didn't obtain better results. The best results I obtained when acquisitions were made with MaximDL - lights / darks / flats and biases. But I had only 5 exposures like this, 90 sec each (lights). The result is great in my opinion, roundness of the stars is 0.084 and I am sure I can increase the exposure time somewhere between 2 and 3 minutes without problems - unguided subs with same great figures. The most important thing to obtain these results is the proper polar alignment. I think a PoleMaster it will be the best improvement ever for this nice mount I have.
  9. You cannot see it because is on the back side of the mount, where the motor is. Is not rocket science, is just a screw that make a lever to push the motor axis on the sector. Is not big deal.
  10. The friction drive can be adjusted with a screw. You cannot preload by pushing the shaft other than using some kind of lever operated by a screw. So is adjustable.
  11. An update to this project. After few runs for testing the pros and cons for this mount, I made some technical adjustments. 1. I had some problems to polar align the mount, due to the fact the polar scope was not illuminated. So I bought a device for this purpose, a part of the modular system of Star Adventurer mount. Problem solved. 2. I had problems to obtain a good focus for the stars. So I made a Bahtinov mask who fit perfect to my Omegon 66 telescope. The Bahtinov mask is a wired one - a mask with some good advantages over a regular one due to the fact an increased quantity of light is getting inside the camera sensor. As a result, you can focus with very short exposures (1), or on dim stars (2) or with narrowband filters (3). 3. I made a huge mistake thinking that the finder is installed on the right position on the horizontal bar (see the pictures from previous posts). The finder is aligned with the main telescope only on RA, but not on DEC. So, to resolve this problem I put a shoe on the main scope and use a lighter finder scope - in this case a green laser or a red dot finder. 4. I encountered some problems when went on the field at night and tried to power the mount from my car battery. The battery had around 13 V when the mount wasn't working but the voltage droped down to 10 V when mount worked. As a result, the mount was blocked after few seconds. So I made a 12 V voltage stabilizer. This device is inserted between the power supply and the control module of the mount and the tension never drop under 11 V no matter what. So now the mount is working in the field too. To be continued with pictures of deep sky objects... When weather will allow.
  12. Hi, As you can see in the pictures with the star shape analysis, the mount is working great, so the concept is very good. Moreover, I am sure the results will be better than usual commercial mounts same class because the friction drive is very stiff an robust and allow greater weights to be worn. The bearing is a radial SKF one and is mounted with a press, like the ones used in the car maintenance. And the machining was very precise being done on a CNC machine wit a high accuracy.
  13. We have an update from the astronomer Pablo Santos Sanz from IAA Granada, the coordinator of this project. He sent us some preliminary data and a map with the observers of this event. Is truly a rare event, as he said in the mail received. " I have generated a preliminary elliptical fit to the shape of Huya that I am attaching (North is up, East to the left). In my attached fit I have removed the scale in kilometers and the observers legend. Data are still under analysis and we cannot provide numbers in order to "protect" the future scientific publication currently in preparation. The additional information you could need: the occultation was observed from 50 sites (involving more than 50 people, including professional -from professional observatories- and amateur astronomers). From this 50 sites 21 recorded a positive occultation. Occultations by TNOs are really rare, and involving an occulted star so bright (about 10 mag) are even more rare. Usually we catch occultations by TNOs in the range 16-18 mag for the occulted stars, for this events we can predict now about 5-10 per month, but we catch positive around only 1 per month (in the best cases). This is the first stellar occultation by Huya, and a record in terms of the number of positive detections! The first stellar occultation by a TNO was detected in 2009 (2002TX300) and up to date we have detected 70 stellar occultations by TNOs/Centaurs (43 by 24 TNOs, and 27 by 5 Centaurs), and we have participated in more than 90% of them! The work to predict one of this occultations is really hard, and can last for years in some cases, due to the high uncertainties in the orbits of the TNOs and the small angular size of these bodies in the plane of the sky (GAIA DR2 is helping a lot, with a very accurate position of the stars). " The graphs down bellow is the photometry analysis for the Romanian astronomers involved in this (only two are a professional but one o them made the acquisitions from his private backyard observatory). I can tell you only that I'm number 7 in that list.
  14. I made some (poor) photometric analysis in MaximDL with my data. What I know is the shape of the light curve is correct. I don't know (yet) how to adjust the parameters inside the program to have right magnitude of the stars. I used 1 reference star and 1 check star. I made 2 graphs - first made from all my data (around 790 exposures) , to see if any other object intersect the path of star light and the second graph made from only 70 exposures centered around the occultation itself, to have a clearer idea about the shape of the curve. Is not to much, but it is fun - I can tell you.
  15. Is interesting that as we know till now, only 14 astronomers had took pictures to this occultation and 11 of them are from Romania. The one who did organize the whole event was Marcel Popescu, a Romanian astronomer from La Palma, so perhaps this is the reason why so many Romanians... Thanks for sharing the program. I will give him a try asap.
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.