Zoe Zontos conducted a CCD imaging project on the spiral galaxy NGC-2403. Using a 20-inch telescope and filters, she took photos of the galaxy and performed calculations on its size and features. Her measurements found the galaxy to be approximately 0.0103 light years across. She also identified and measured two H II star formations, the largest being 0.0969 light years across. While she was pleased with her first attempt, Zoe plans to improve her techniques and gain more experience in future observational astronomy projects.

1. Zoe Zontos
NGC-2403 CCD Imaging Project
The objectof concentrationformyprojectwasgalaxyNGC-2403; thisspiral galaxyisalsoknown
as Caldwell 7,andit islocatedinthe constellationCamelopardalis.Thisgalaxywasfirstdiscoveredin
1788 by WilliamHerschel,anditisa part of the Messier81-Messier82 (M81/M82) group and locatedat
an estimated8millionlightyearsaway(Plotner).Ithasa magnitude of withinthe range of 8.4-8.9, and
itsdiameterisestimatedatabout50,000 lightyearsacross.In 1954 and 2004, two supernovae were
reportedtobe seeninNGC-2403. Also,NGC-2403 containsa large numberof H II star formationswithin
its50,000 lightyeardiameter(“NGC-2403”).Ichose thisgalaxyto observe andfocusmyprojecton
because Iwantedto photographandobserve myfirstgalaxy.The moonandcertainnebulasare often
the focusof studyfor manystudents;Iwantedto focusonsomethingdifferent.Also,manyother
galaxieswere difficulttoobserve because of theirspecificrightascensionsanddeclinations;manyof the
galaxiesIhadpreviouslychosenare notobservable fromDaytonaBeach.The galaxyof NGC-2403 wasa
convenientchoice because of itsopportune rightascensionanddeclination.
For thisproject, IusedSAOImage DS 9 and MaxIM DL 5 to photographandmake calculations
for NGC-2403. With the 20-inch CDK telescopethatIusedto photographthe galaxy,Iuseddifferent
filterstoimage it;the three filtersthatIusedwere ‘i‘,‘g’,and‘L’. InSAO Image DS 9, I tookpointsfrom
an image of the galaxy:X1 = 519.538 pixels,X2 =712.720 pixels,Y1 =764.731 pixels,Y2 = 735.011 pixels.
Usingthe conversionof 1.1625 arc seconds perpixel,IusedPythagoreanTheoremtocalculate 195.45
pixelsandconverteditinto 315.163 arc seconds.Then,usingthe conversion of 1 parsecbeing3.26 light
years, I took the arc seconds,converteditintoparsecs,whichcame outto be 0.00317 parsecs;thenI
convertedthatinto0.0103 lightyears.So,if I didthe calculationscorrectly,the distance acrossthe
galaxyinthe photoof NGC-2403 is0.0103 lightyearsacross. Convertingpixelsagain,Ifoundthatthe
photoof NGC-2403 has an angularsize of 1.818 microradians;if I didthe equationcorrectly,thenthe

2. distance of NGC-2403 should be 1.744 parsecsaway. Lookingat the imagesindifferentfilters,Ichose
twoareas inthe galaxywhichIthinkare twoH II star formations,the largestandthe smallestthatI
couldfind.Doingthe same calculationsasI didforthe whole galaxy,Icalculatedthatthe largestHII
formation tobe 20.88 pixelswhichconvertedto33.669 arc seconds,0.0297 parsecs,and 0.0969 light
years.For the smallestHII formation,Icalculatedittobe 4.12 pixelswhichconvertedinto 6.644 arc
seconds,0.151 parsecs,and0.491 lightyears. I didmybestwiththese calculations;Ihope theyare
somewhataccurate giventhe conversionsandthe equationsthatIused.These are the calculationsthat
I attemptedtomake withthe CCD imagesthatI obtainedforNGC-2403.
Despite the rathersuccessful attemptatgatheringandcalculatingdata,IbelieveIcanmake
significantimprovementsthe nexttime Iworkona projectsuch as this.Now that I know how to use
imagingsoftware better,Icancreate betterphotos. Also,I now have an ideaandsomewhatof an
understandingastohowto go about thisprojectnexttime;Iwill make evenmore precise andaccurate
calculationsandmeasurements.AnotherthingIwill make sure todonexttime istake more CCD images
and use more filters.Iwill alsoparticipateinmore observationsessionsbecause Idonotbelieve that
twosessionswasenoughtogainthe bestdata. I couldalsotalk to anotherspace physicsorengineering
physicsmajor(one whoismore advanced) toask themfor theirhelpinunderstandinganyconceptsin
imagingsoftware andthe telescopethatare not extremelycleartome.However,overall,Ifoundthat
thiswas an amazingproject,andI wasveryexcitedtoworkit.As I advance inmy degree,Ihope todo
more projectslike thisandgainmore experience inthisareaof observational astronomy.
Images

3. Above isan ‘i’filterimage of NGC-2403.
Above isa ‘g’ filterimage of NGC-2403.

4. Above isan ‘L’filterimage of NGC-2403.
Above ismyattemptat addingcolor to the CCD images.Ididmy best.
If you wouldlike tosee myotherraw-filteredimages,justletme know.

5. Works Cited
"Hubble LawLab Exercise." HubbleLawLab Exercise. N.p.,n.d.Web.10 Apr.2013.
"NGC 2403." Wikipedia. WikimediaFoundation,19Apr. 2013. Web. 24 Apr.2013.
Plotner,Tammy."A NewSpinOnNGC 2403." UniverseToday RSS.N.p.,5 Mar. 2011. Web. 20 Apr.
2013.