Periodic Error Correction

Worm gears in the mounts has an inherent error where they introduce a star going back and forth in the image, resulting in a not a perfect round star. Worm gear cannot be made perfect.

Since this is a periodic error, this problem can be reduced by using software to figure out the error and then tell the mount how to move in order to solve the issue. This is called Periodic Error Correction.

Pempro is an amazing software which i have used to ‘perfectly’ polar align my mount and the minimize PE. Recently i had opened the whole mount and cleaned and re-greased everything. Later i put a lot of effort to properly, as far as i can, adjust all the gears back. and today i ran Pempro and here are the results:

 
 

On the top right is the PE which is stunningly good for my mount.. i would want to believe that something is not right.. an error of just and arcsond.. really? is Losmandy Titan such an amazing mount? I am very very happy with these numbers.. but seriously.. 1 arcsecond?

ZWO 183 CMOS Linearity Test

A quick linearity test of ZWO 183 CMOS chip.. this is so surprising.. the linearity goes above 60k ADU. Is the CMOS chip that good or am i doing something wrong here?

Tpoint Pointing Model Automation

Making a star pointing model is extremely important to use your telescope properly.. without it you won’t be able to see any object in the sky.

Making a pointing model with a camera is not easy either. In the past, i have spent hours and hours in a session to make a model manually for about 50 stars. The problem has always been my super small Field of View which used to 8*8 arcminutes.

Enter the new world: Wide Field of View!

Installing new equipment had given me over a degree of FOV and now is the time to try automating pointing model. So tonight i did exactly that.. Lo and behold.. this is the result:

This is the path automation followed and the circles are the spots where the exact telescope’s position was noted. In numbers, 85 points were added. Now finding any object will be a breeze by my C14 telescope. Thank you Tpoint!

Telescope Corrector Plate cleaning

This alone is the work i always want to avoid.. cleaning the corrector plate of C14 telescope. It always damages the coatings of the optics, ever so slightly but nevertheless i have to do it after a couple of years or so.

It is not at all easy to find 95% isopropyl alcohal in my city; there is only one place that i eventually found this in Lahore.

Distilled water, isopropyl alcohal and surgical cotton is all i need to do the cleaning process.. look at the difference now.. Telescope is happy now :)

Temperature dip in the observatory after opening the roof

Upper Graph: Inside observatory temperature 

Lower Graph: Outside observatory temperature

So the highest temperature today went to about 35 C. I kept the roof of the observatory closed and opened it around 22:30. Notice the sudden dip in the upper graph. This shows the sudden release of the heat trapped inside the observatory even after 4 hours of sunset and then the heat loss ratio became stable.

Lower graph shows the temperature loss outside the observatory.. of course no sudden dip around 22:30.

Mare Crisium

Here is how a sunset looks like on Mare Crisium, a beautiful crater on our Moon.

Telescope: Celestron, C14

Mount: Losmandy Titan, tracking in Lunar mode

Camera: ZWO ASI 174 mono version

Filter: Luminance

Image Exposure: 1/1000th of a second

Total Frames: 4000

Stacked: 1000

Software: Fire Capture, AviStack, Registax, Photoshop CC.

Mouse in the Observatory

Yesterday i thought to get some Photometry data because the fog was not intense and the humidity was 70% in the evening. Little did i expect what was for me there in the observatory!

When i opened the Human Room, THIS is what i saw:

Two wires have been cut (marked with arrows, showing both ends) and some polystyrene sheet has been damaged. Immediately a picture of the mouse appeared in my mind.. this is bad!

I tried to find the mouse inside the room but it is filled with a million things. I knew he must be hiding now somewhere here and perhaps he is not even here right now but i had to do a thorough search.

Finally i found him.. the enemy was hiding deep in the back corner of the freezer. I tried to convince him logically that he cannot live on my planet and he should go back to his own but for some unknown reasons, he did not respond.

Then i had to do what an angry Samurai would do.. I threatened him with my martial arts skills. He got furious and suddenly jumped and started running everywhere. Believe me, when it moved, it moved faster than the speed of light (no disrespect to Einstein).

I tried to show him the outdoors respectfully but he was in no mood to move out. At one point, i lost him. Tried to locate him everywhere but in no vain. May be he has gone out of the room after all but i had to confirm it.

Suddenly i remembered that i have a Thermal Imaging Camera from Seek Thermal which can be attached to the iPhone. Immediately connected it and started scanning the room. It was not on the floor or behind the wires or tables.. perhaps the thermal camera cannot pick out his heat signature.

But then when i pointed the camera on the wall.. I saw this view:

Right is the normal view and left is what Thermal Camera is showing me. The devil was inside the wall!!! This is becoming so Tom and Jerry now!

I finally made so much noise and hits to the wall that he came out and after another 10 minutes or so of me being chasing him out, he finally decided to end my cardio and left with the grace of Splinter (yes, i was also a child once!)

Changing Temperature's effect on focusing

When i connected the telescope and camera today with my computer, the TCF Focuser temperature readout showed the temperature of the telescope to be 18 C. I thought let's experiment on the temperature and defocusing simple relation.

I focused the telescope on a readout at 4,000, which is the position on the TCF auto focuser. Kept on imaging for a while and when the temperature went 2 degrees below at 17 C. I refocused again and got a number of 4,499.. so the focus has been shifted around 450 values.. this is a huge difference!

The following picture will illustrate it better.. Notice the pointed star in both images. The left shows the FWHM value of 3.45 at the temperature of 17 C, this is rather a blurry star now but it was at tight focus when i focused it at 19 C.

On the right is the same star at FWHM of 1.88 at 17 C but after refocusing.. this is much much better.

So with 2 degrees of temperature drop, the FWHM of the star increased from 1.88 to 3.45! This translates as a very accurately focused start to a poorly focused star. What i want to show is we need to constantly keep an eye on focusing. That is why the high end focusers come with the temperature compensation option.. I always keep my system at the temp compensation mode. This keeps on changing the focuser position by noticing the change in the temperature. TCF can detect a a change of a tenth of degree!

Oh and btw, for those who don't know know about it. FWHM is a widely used number to see how small a star is in any image. The lower number is always better. Web has a lot of sources about it.

The Mighty Lunt 152!

Here is a view of my big Solar Telescope.. The Mighty Lunt 152mm (6 inch lens), which shows (only) the photons being emitted at Hydrogen Alpha line which is 656.281 nano-meter. And this is where all the action of hot plasma (soraj se nikalti hoi aag) really is.

Lunt 152 just minutes before Solar Outreach at AIMC, Lahore. 

Lunt 152 just minutes before Solar Outreach at AIMC, Lahore. 

Official Inauguration of Zeds 2.0

"On this date; the 6th day of April, the year 2016 A.D"
To celebrate the official inauguration of Zeds 2.0, Aamna Saleem brought this cosmic version of a cheesecake. Thank you, Aamna!

To celebrate the official inauguration of Zeds 2.0, Aamna Saleem brought this cosmic version of a cheesecake. Thank you, Aamna!

It is finally ready! The extension to the original Zeds Astronomical Observatory, after 12 years of the initial observatory construction, is finally here! Enter: Zeds 2.0 ! An observatory that can house 3 telescopes at any given time, ready for use.

Cutting the celebratory cake for Zeds 2.0

Cutting the celebratory cake for Zeds 2.0


The inauguration day was celebrated by setting up Sameer Rashid Shami's Celestron 8SE telescope on top of the Celestron AVX mount. Sameer had waited a really long time (almost a year) before the appropriate testing could be done (water proofing, electrical wiring and gauging weathering effects) to allow moving in the equipment. 

The Celestron 8SE on top of the Celestron AVX mount; looking rather ominous!

The Celestron 8SE on top of the Celestron AVX mount; looking rather ominous!

The observatory has a roll-off roof that is more than twice the size of the original telescope room for, what can now safely be assumed to be Zeds 1.0! Currently it houses 2 telescopes. One being Sameer's 8" SCT on a Celestron AVX mount, the other being CBSAP 127mm Apochromatic refractor on a Celestron CGEM mount.

First light image from the new observatory. This image shows the galaxy pair M51 also known as the Whirlpool Galaxy, named after its conspicuous display of beautiful spiral arms. What is also evident is a smaller companion galaxy seen up top that is…

First light image from the new observatory. This image shows the galaxy pair M51 also known as the Whirlpool Galaxy, named after its conspicuous display of beautiful spiral arms. What is also evident is a smaller companion galaxy seen up top that is in a cosmic ballet with the bigger, more massive partner below. 
Image credits: Sameer Rashid Shami
Telescope and Camera: Celestron 8SE, SBIG STF8300 monochrome CCD
Autoguider: SBIG STI monochrome CCD

In the coming days, in addition to imaging galaxies, star clusters and planets, the new observatory is planned to be used for gathering photometric as well as spectroscopic data for stars and star clusters as well as astrometric data for Asteroids and Comets.

Bright days (or rather, dark nights) await us in the future!

LET THE OBSERVATIONS, BEGIN!

M13, Globular Cluster

 
 

M13 Globular Cluster (NGC 6205), also known as Great Hercules Cluster, is a globular star cluster about 25,000 light years ( 2.36*10^17 km) away from us. It is first discovered by the famous Edmund Halley in 1714, who wrote:

"it shows itself to the naked eye when the sky is serene and the Moon absent"

William Herschel mentioned it in these words:

.. most beautiful cluster of stars, exceedingly compressed in the middle and very rich"

A distance of 25k light years and with the angular diameter of 23 arcminutes, the actual size of this cluster comes out about 150 light years. Towards the center, the star density is about 500 times more than our own solar neighbourhood. If there is a planet in the center of the cluster, the night sky would be blazing with literally thousands of stars much brighter than Sirius and Venus. 

M13 Cluster is also famous because, once we have sent a radio signal to supposed Aliens in this cluster!

Omega Centauri is the largest Globular Cluster in our Milyway Galaxy.. here is the comparison of M13 with Omega Centauri:

This image is a work in progress and I would be collecting more data of this cluster in the coming weeks. Stay tuned!

Equipment:

  1. Celestron C14
  2. SBIG ST9XE
  3. SBIG AO8
  4. Astrodon Luminance Filter
  5. Maxim DL
  6. Photoshop

2 hours of exposure, subs: 120 sec

New equipment at Zeds

So i have been doing photometry with Astrodon V filter for sometime now. But i wanted to do more science at my observatory. 

For Photometry, next step was to invest in more filters. Recently ordered Astrodon Blue and Infrared Photometric filters and they arrived yesterday.

 

Parcel from UPS

Parcel from UPS

Astrodon Photometric Blue and Infrared Filters

Astrodon Photometric Blue and Infrared Filters

image.jpg

With these filters, i also got Bahtinov Mask from Farpoint which will be used for CBSAP 127mm APO refractor. 

Farpoint Bahtinov Mask

Farpoint Bahtinov Mask

These filters are now in place with their other cousins in SBIG CFW10 filter wheel. 

 

image.jpg

Now where is the clear sky? 

Dr Hoodbhoy's Lecture on Blackhole

Dr Pervez Hoodbhoy, honored us all by coming to Zeds Astronomical Observatory to deliver a lecture on Blackhole and Information problem, on Lahore Astronomical Society's monthly meeting of April 2015.

I am truly grateful Dr Pervez Hoodbhoy, for coming here and enlightening us about the amazing physics of Blackholes. Every participant learnt a lot from you and enjoyed your pleasant company.

Here is the recording of the whole event.

Sunset at my Observatory

Yesterday evening was beautiful at the observatory. I opened Canon 6D and took around 10 images of western sky. Moon in Hyades, Venus, Orion, Taurus, some Auriga and even Pleiades in the lower horizon.

I could spot, barely, a 5.8 magnitude of star in Pleiades.

New and a Big toy at my observatory

Here is the announcement: I am now the proud owner of Lunt152 Hydrogen Alpha solar telescope!

My experience with Lunt60 telescope, which has of course 60mm aperture lens, has been really fascinating, from super sharp views of the prominences and solar atmosphere, to very detailed images.

Meanwhile i had been watching images from 152 aperture telescopes and those images are literally out of this world. Aperture envy in astronomers does have its reasons.

On 3rd of December, i received my shipment on Lahore Airport Cargo area via FedEx. Lunt152 is big and heavy and cannot be used on previously owned Celestron VX Mount so i also bought Celestron CGEM DX Mount which is much better in handling the big scope such as Lunt152.

First look at the boxes outside the cargo area

Lunt152 carrying case unboxing 

After reaching home, i could not wait a moment and immediately started fixing the mount only to discover that i cannot place the telescope on the top because the dovetail bar Lunt152 comes with, is far too thin for CGEM to grip it.. not happy.

The issue is, everything one needs about telescopes and mounts etc here in Pakistan, one has to buy it from the outside. I needed it to be made locally and locally i got it made. Yesterday i installed it at my observatory building and this thing is Huge folks! Here is how it all looks.