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1000th Session;
ETX-90RA becomes an ETX-90EC; iPhone Lunar Imaging

Posted: 15 July 2016

As I reported from a previous session, the 18 year old Scopetronix MicroStar II+ on my old ETX-90RA no longer reliably slewed the telescope in Right Ascension and Declination. I had many years of use of this fine accessory by Jordan Blessing (thanks Jordan, wherever you are now). Several years ago I received an ETX-90EC base. On Thursday, 14 July 2016, I unboxed the EC base and first checked it out using a Meade Electronic Controller handcontroller. Slewing worked as I hoped. Knowing that the base motors and electronics still worked, I deforked the ETX-90 OTA (optical tube assembly) from the RA base and attached it to the ETX-90EC base. I then tested the ETX-90EC using an AutoStar #497 indoors. The fake alignment worked as expected and slewing worked fine. Then I switched the ETX-90 from the Meade #883 tripod I had been using with the ETX-90RA to a Meade #884 tripod. I did a CALIBRATE MOTOR and TRAIN DRIVES to get optimum performance from the AutoStar #497 with the ETX-90EC.

The photo at left below shows my "ETX Astro Telescope" (as it was originally called, later being known as the "ETX-90RA") shortly after purchasing it in September 1996. The photo at the right is its current configuration on the ETX EC base and #884 tripod.

photo photo

I thought I had kept a note about the ETX-90EC base donation but couldn't find it. If the person who donated it to me sees this, many thanks!

I did find the ETXtender Focus Knob for the ETX-90RA that I received in March 2000. Since I was no longer going to use the MicroStar II+ which had an electric focuser, adding the ETXtender really helped with focusing.

I hope to get many more years of use from the "Mighty ETX".

Open: Thursday, 14 July 2016, 1909 MST
Temperature: 98°F
Session: 1000
Conditions: Mostly clear

Equipment Used:
1.25" 26mm eyepiece
1.25" 3X TeleXtender

iPhone 6s Plus

I set up the "new" ETX-90EC in Alt/Az mode on the observatory patio. This night's tests would confirm that the old ETX-90EC base can still properly GOTO and track objects.


1935 MST: sunset. 1936 MST: Jupiter visible with naked eye. 1938 MST: Mars visible with naked eye.

1940 MST: ETX ON. Faked the star alignment as stars were not yet visible. GOTO Jupiter put the planet near the center of the finderscope field-of-view (FOV). Viewed Jupiter, 48X. Nice view of the planet's cloud bands and the four Galilean Moons. Using 144X the view of the planet was good.

Then slewed to the star Spica, which was now visible, and SYNCed the AutoStar.

GOTO Mars and viewed it, 144X. Seeing was not great but some surface details were visible.

Next, viewed Saturn, 144X. Cassini Division was visible. At 48X the moon Titan was visible.

2004 MST: viewed the waxing gibbous Moon, 48X. Lovely views along the terminator using 144X.

Began setting up for iPhone afocal imaging. Mounted the iPhone 6s Plus on the ETX-90 using the SteadyPix afocal adapter. This is the Moon, afocal 48X:


I used the Apple Watch as a remote shutter release with the Camera app. Here is how the Moon looked live on the Watch at 48X:


I then did a series of images, afocal 144X, along the terminator:




2025 MST: ended iPhone imaging. Did some more lunar observing, 144X.

I then switched to the William Optics Binoviewers:


Wow! Great views of the Moon, 62X, using both eyes. The entire Moon was visible and nearly filled the large FOV.

2036 MST: ETX OFF. Alt/Az tracking this night was not too bad for a mount that had not been used for several years. Overall, the tests of the newly mounted ETX-90EC were successful.

Close: Thursday, 14 July 2016, 2050 MST
Temperature: 82°F
Session Length: 1h 41m
Conditions: Clear

This was the 1000th session in Cassiopeia Observatory since it saw "First Light" on 18 August 2009! This table shows how many sessions occurred each year:


2016 has been a year of upgrades. Some were planned, like the 8" LX200 to 12" LX600 upgrade, addition of a pier in the observatory, and the installation of a POD Zenith Table (PZT). But three others were unplanned: the observatory carpet replacement (scheduled for Monday, 18 July 2016), moving the 11 year old ETX-105PE OTA from its original base to the 13 year old LXD55 GEM, and now moving the 20 year old ETX-90RA from its original base to an ETX EC base. I had expected to be using the 12" LX600 for this 1000th session, but it seems appropriate that I would be using the ETX-90 instead.

The past 1000 sessions have been enjoyable and I look forward to the next 1000 sessions in Cassiopeia Observatory!!

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