How to calculate the step size for auto-focusing

Autofocus method
Data 
                                                                                                       At
Bin                                          1x1 and 2x2
Telescope FL                         1400
Pixel size                                9
Read Noise RMS                  10e-
Number of steps                    105000
Resolution per steps              0.083  Micros/step
travel                                      0.35" 8.89mm

CFZ                                                                                                         Critical Focus Zone
Ha  3nm           656.39                                                                                 95    
OIII                   500.17                                                                                72
SII                    671.69                                                                                 97
Red                  650.94                                                                                 94
Green               510.74                                                                                74
Blue                  475.69                                                                                69
Formula
CFZ / Focuser step size    Multiple  by 1.5 and 2                                       

Step Size     95 / 0.083 x 1.5 = 1716

                                                                                                                          Step Size 


                                                                                                Ha       OIII       SII          Red   Green    Blue
(CFZ / Focuser step size) x 1.5 = focuser step size                1,716  1301   1753     1698     1337    1246
(CFZ / Focuser step size) x 2 = focuser step size                   2,289  1734    2337     2265     1783    1662

So, if you are using SGP for example, in the step size you insert the corresponding step size. The 1.5 figures are the lowest  step size and the 2 figure is the highest.
You will need to play round say from 1716 (if you are using Ha filter) to a maximum of 2289.  I tried the 1716 and it was good from first time.

Back again to my observatory

 After almost five months I was able to travel to my observatory in Southern Spain, due to travel restrictions we had to stay within our province here in Spain in the Andalucia region. It was a real pleasure to see that no damage to the equipments, especially after having really stormy weather during this time. After  cleaning the inside of the dome, everything worked fine, just  SGP software subscription that needs update.

My first telescope and programs

 The following are pictures showing my first automated system going back 5 years, it wasn't even on a good location , between block houses!!. But I had to start somewhere and this was just the beginning.

Unpacking new telescope -RH250 MM Officina Stellare

 I received my new telescope around six months ago, but I have had little time to take pictures of the  telescope inside the dome.

But I do have some images unpacking it when it was delivered. 

The telescope is a RH Veloce 250, design which allow a fast F/Ratios with high definition over a wide and flat focal plane. It offers a pinpoint star all over the FOV..

https://www.officinastellare.com/professional-telescopes-prod/rhveloce/rhveloce250.html

https://www.officinastellare.com/os_uploads/files/RH250_WEB.pdf

Building the set-up

 

Coming from the Moonlite 3,5 focuser which replaced the original Stellarvue 130mm focuser, you need to be careful given that latter focuser is shorter by around 130 to 150mm meaning to reach focus you will need to reach 212mm.

Image Train from the focuser

Extension tube 

Stellarvue Flattener

Precises Adapter from Flattener to Baader Filter Holder

Baader Filter Holder

Precises Adapter from Baader to QHY268C camera

QHY268c

Distance from the Flattener to the Sensor should be 79mm

PUTTING IT TO THE TEST

Since I have gotten the camera, my weather has not been cooperating much, I have not managed to get a few images. I will be using the Stellarvue F7 -130mm telescope  in my Bortle 5 skies (approximately 20 average SQM) with an Astronomik L2 UV/IR cut and  5nm H-alpha for the H-alpha image.

In my initial testing the camera did not cool lower then -15C this is my only complaint I had, the cooling was not as good as other cameras I’ve used, I can imagine that living in southern Spain does not help to lower that temperature.

Hopefully, once I complete mapping the night sky using ModelCreator, averaging around sixty sky points location and with a prior Sharpcap Polar Alignment, this will be sufficient to create a proper stable pointing mount.

For automation the entire system I will be using SGP. The mount will be connected via a network cable, the USB3.0 hub is connect from my laptop via a fast USB3.0 8 meters long cable.

New Scope : The Stellarvue SVX130T

The Company has currently have completed a number of 130 apo triplet objectives at better than .99 Strehl.

Air-spaced lenses that are 5" and larger are often mounted in aluminum cells. These cells expand and contract many times more than the glass. The larger the lens is, the more important it is to have it mounted in a cell with a similar coefficient of expansion (CTE). LZOS in Russia has always provided their 130 mm and larger lenses in a steel cell for this reason. Many other 127 - 130 mm refractors use simple aluminum cells which expand and contract around the glass many times more than our cells, distorting the image. Using a material that closely approximates the expansion and contraction rate of the glass is heavier and much more expensive, but it maintains the performance of the lens despite dropping temperatures.

Arrived!!

 

 

 

CMOS QHY268C arrives

After a long wait mainly due to factory delay in production the camera is here. In my previous post I described the camera specification, my next step is ordering from Preciseparts adapters to connect to a Stellarvue 130 telescope Fatterner. Investing in this OSC camera has been  long time coming, especially now with the development of the CMOS cameras, they are the future, I believe that they will surpassed the CCD cameras.

 

 

Lick on this link, its explain in detail the Gain of the camera.

https://www.youtube.com/watch?v=MiBHQ2jPzV4